Most readers, and most authors, eventually realize that such constant interruptions to narrative flow are bloody annoying. Yes, there are a few who claim to like them, but they're a distinct minority. Vocal, but a minority.
The problem is translating a game mechanic into a setting where said game mechanic is pointless. In a computer or tabletop RPG, you need such a system because it's the only way of evaluating how a given character is doing due to the limitations of technology in an efficient manner. In prose, such a technique is pointless because the author is capable of getting inside the characters to show what's happening. You don't need to say that a hit was for 25 HP instead of the normal 10 HP because you can simply describe the fact a character was hit by a really hard blow that sent them reeling. You can show them getting tired instead of simply listing off dwindling stamina points. You don't need to say that you blocked 9 points of damage and only took 1, because you can describe how a blow was blocked and barely caused a nick, and so on.
The other thing is that, in real games, you do not see this happening:
Okay, I just levelled up and got 1 point I'm going to put into Strength, so I now have 15 Strength, 20 Perception, 12 Endurance, 8 Charisma, 9 Intelligence, 16 Agility and 13 Luck (list all the other stats the character has).
(Three pages later) Oh, levelled up again! So one more point in Agility, so now I have 15 Strength, 20 Perception, 12 Endurance, 8 Charisma, 9 Intelligence, 17 Agility and 13 Luck (list all the other stats the character has, none of which have changed).
(Five pages later) Oh, levelled up again! I'll drop another in Intelligence so now I have 15 Strength, 20 Perception, 12 Endurance, 8 Charisma, 10 Intelligence...
If someone actually did that, other players would beat them senseless for wasting time needlessly repeating things that are already known and especially that did not change. Yet some LitRPG authors start off doing this. It's pointless and absurd and annoying filler, and some/many authors and readers eventually come to that same conclusion. What's more important is quite often said numbers are (a) utterly pointless, as characters defeat enemies that by all rights they shouldn't be able to even score hits on due to level differences, and (b) most authors aren't game designers, so unless they specifically rip-off an existing game, usually the numbers wouldn't even make sense in creating a game people that wasn't an illogical, bug-ridden, unplayable, and unenjoyable piece of garbage.
Another factor, which should be taken into account, is that as tech improves those kind of mechanics aren't as necessary. Many computer games now don't spew out numbers, they simply show graphical effects to indicate what's happening. And, in one of the single most annoying things I see in LitRPG, if you have full-immersion VR, these sorts of things are utterly unnecessary for the same reason the prose makes it unnecessary. I don't need numbers to tell me I'm getting the crap kicked out of me if I can feel I'm getting the crap kicked out of me.
Other mechanics, like pop-ups providing information, don't require the reader to be reminded of the information constantly. The first few times the player/protagonist gets a skill that lets them, say, identify the type of enemy they're facing with a small window that pops into their field of view, fine, but after that constantly reminding the reader of it is akin to showing that a character has a cell phone, but thereafter always making a point that the whenever the character makes a call they haul out their cell phone. Great, wonderful, thanks for reminding me for the 20th time they have a cell phone.
If the character looks at an enemy and the author simply notes what it is, the reader takes it for granted that there's a little window that popped up that provided the info. They don't have to be constantly reminded unless something different happens: the window, for some reason doesn't provide the information for instance.
To take it away from games for a bit, imagine how annoying something like this would become:
My Uncle Bob, who is my uncle because he's my father's brother, was at the park when someone came up to him and said, "Hey, Bob!" Bob, my uncle, responded with a cheerful hello, as Uncle Bob does when he talks to me, his nephew. Because Uncle Bob is a really good guy, and although as I am Uncle Bob's nephew I could be biased, I don't think so because everyone thinks Bob is a good guy, even though, unlike me, his nephew, he isn't their uncle.
And for the rest of the story, every time Bob was mentioned, everything grinds to a complete halt to remind everyone that Bob is the narrator's uncle. That's what continually tossing in those reminders that the characters are in a LitRPG story is like.