The main benefit is that people see your copyright as legitimate.
To be sure, some people take ebooks and copy them and stick them right back on to Amazon under their own name and with all the money going to them. It's not super common, but it does happen. Someone I know, a published cookbook author, discovered someone had done this not just to her books but to several other people's. Stole her titles, artwork, everything. Amazon was far less responsive than they should have been, but it finally got settled.
This pales in comparison to what happens when you put content on a blog. The content skimmers swoop in and suddenly your work isn't just on one Amazon book site, it's on 500 sites all over the internet.
I have a blog that's mostly recipes and I find my recipes literally on dozens of websites. Each recipe I mean. The totality, well, I can't count. Sometimes they credit me and give a link back to my blog (though it's all done without my permission). Sometimes my name is there with no link (or a link with no name). Usually, it's just copied wholesale with no acknowledgement at all.
While I'm sure the professional content skimmers (they make money by hosting ads on the pages with the stolen content) know what they're doing is illegal, lots of other people will steal your content and think it's perfectly okay. Few think it's legal to use another person's article and put your name on it. But most people think that, if it's on the internet, it's theirs to do what they want, as long as they credit you (though credit tends to drop off after a couple pass-arounds, whether it's email, social media, or reblogging.
Even though you can't stop all copying, having your work in book form will help make it yours. Claiming authorship of an article found on 50 other sites is a bit harder, because of the above.
The disadvantage is fewer readers.
People Google what they want, they don't go look up books on Amazon if they are just looking for an article. If you charge for the work, readership goes way down. If it's free, it's still not as straightforward to find. Though you can put links on your website and include enough content there to get hits from search engines.
The other disadvantage is you need to format for Amazon and they have some rights. With a website, you have full control.
I just use my blog, and I'm resigned to the fact that a lot of my content gets stolen. If I were writing something more formal, I would likely change that.
One possibility is to give teasers to the articles on your website but make the full piece a free and easy to download PDF. That should limit the automatic content skimming.
