Is there something you can achieve without a overarching plot that you can't with one? Let's say you write a collection of short stories ala The Witcher, is there any good reason why you shouldn't have a overarching plot? I am wondering if an overarching plot is always recommended or if people have experimented in the past and tried to write a book without an overarching plot to achieve something that couldn't have been done with an overarching plot.
People have in the past written books without overall plots, but I think it was more because the desired effects did not require such a master plot than because having one would have caused a problem.
One common form is a collection of separate stories with a common setting , perhaps some common characters, but no clearly linked plot. The Dying Earth by Jack Vance comes to mind. This form allowed him to display his unusual setting in a series of slices. Each slice had a very distinct plot, and there were some relations between slices, but nothing essential. Having an overarching plot would have required fitting each slice into that plot or discarding any that did not fit. Note that Vance's later books with the same setting The Eyes of the Overworld and Cugel the Clever do have overarching plots, and indeed the two form a single story arc. These are also sets of related stories or episodes (originally published separately) , but they share a common PoV character, and one episode follows directly on another, building on the situation created by the previous story, and allowing continuing character development. The major plot problem is not so0lved until the end.
Another form that often does not have an ovearching plot is the memoir. As life usually does not have a master plot, a realistic memoir may not either. Examples that come to mind include The Years of the Forest by Helen Hoover and Adventures in Contentment by David Grayson. Here attempting to impose a plot would have distorted the works. Biographies generally have the same issue. So do accounts of real events, such as The Brethren: Inside the Supreme Court by Woodward, or My Life in Court By Nizer.
Some novels have a plot which is more or less just "and then this happens". Sometimes this can feel overly episodic, but sometimes not. One very popular example is the Aubrey/Maturin Novels by Patrick O'Brian. These are naval adventures during the Napoleonic Wars, for those who do not know them. There are several multi-book plot arcs, but sometimes one plot arc ends and another starts in mid-novel. I was recently re-reading The Reverse of the Medal The first section is devoted to seagoing adventures, including one episode where one ship chases another, very excitedly told. These tie up the plot arc from the previous novel The Far Side of the World Then the ship lands and the crew is dispersed. Captain Aubrey is tricked into some unwise investments, and then is accused of what we would now call insider trading, and brought to trial. The two sections have no obvious connection, although it later turns out that an adversary from two books before (Treason's Harbor) manipulated the situation. This has some of the effect of a biography, and in this case it is well done and it works.
So it is surely possible tom have a book with no overarching plot, and this permits some effects which might not work if a master-plot was present. But if a plot fits a book, there is no reason it should not have one, in my view.
Per the comment, a good reason you should have an overarching plot is to avoid the stories being too "episodic". Serial writers can't change things too much in one single episode, without a master plan, because with older parts of the story released, it's often difficult or impossible to go back and say "what really happened was this". Unless you're George Lucas, but that's a special case. Anyway, when you're writing a sequence of stories, if the end of each one leaves the universe in the same state in which you found it, then while it's easy to pick up where you left off for the next story, the story you just wrote likely has little meaning to the reader/viewer, because nothing changed. So, even sitcoms and other prime-time TV entertainment create arcs over seasons and/or the entire series, with incremental character development through each episode towards end goals in mind for the overall story being told about these characters.
Now, there's a disadvantage to story arcs. First off, even though it's how we tell stories, they aren't realistic. Olympic gold medalists get up the morning after the medal ceremony and continue their lives. People who die are survived by those who don't. Real life doesn't come to a conclusion. This is often played with by ending a story without actually concluding it. It's a literary risk, because it specifically subverts our expectation of having what we just saw/read get wrapped up in a bow and dropped in our lap. However, you as the author have to stop writing at some point, even though we subconsciously know the lives of the characters continue (unless they don't, which is a fairly powerful "conclusion").
The second major disadvantage of a story arc is that trying to continue past the planned arc can feel like you "jumped the shark". Which is partly true; you intended the narrative to end at "happily ever after". "Happily ever after" implies no further conflict, no more enemies, no more drama in the lives of the characters you created. In short, no real reason for people to continue to be invested. Sondheim specifically played with this in "Into The Woods"; "happily ever after" is just the end of Act I, with Act II showing us that it in fact isn't always "happily ever after", and living in a fairy tale can be exhausting.
To keep the reader engaged, you have to invent new conflict, create new enemies, and inject new drama into the "happily ever after" that you tied up in a knot at the end of the last story. This often isn't easy, especially if tying up loose ends means one or more key characters, good or bad, aren't around anymore. If the Big Bad of your show or book series dies in Book/Season 7, you need a a reason to write Book/Season 8. The most common such reason is a Bigger Bad, who in some way is even more of a threat than Big Bad was. If the main character's key love interest died killing the Big Bad, you need a reason for the main character to want to fight Bigger Bad when they already lost everything they care about in their victory against Big Bad.
This continuation often feels artificial, often because it is; the writers ran out of ideas, the producers decided to end the series with the big finale arc they had planned, and that generates such buzz about the show that the network convinces the production to keep it going. The "right" answer is "no, let it be done, we'll come up with something new", but what's the "right" answer worth when this series is your first big success, and Season 8 is a guaranteed $2 million an episode?
The best writers know how to split the difference, creating a narrative that comes to a natural stopping point in the telling, while not wrapping things up so tightly that it's difficult to pick the story back up. Writers, even some of the literary greats, often find themselves unable to cleanly create mini-denumons in a large arc, and end up writing epics that often have to be artificially split into practically-sized books. Tolkien's Lord of the Rings is only the most well-known example. Good people in the editorial process can make it feel less artificial, but it's ideal if the writer approaches a larger arc with at least some idea of where they're going to tie the bale of each story, and always leaves one story with the possibility of another, even if no-one knows what it would be.