Floating windows is kind of a big deal.

Imagine not having a full screen spell check suggestion window, but instead a little context menu that pops up where you can pick a suggestion while still being able to read the original buffer that you're trying to spell check. Sort of like what Sublime Text had forever.

Or little snippets of helpful text for git specific details or inline documentation for auto-complete.

I've only been using Vim for about 8 months but floating windows is something you severely miss having previously used other editors like VSCode. Now with them in tact, it will unlock all sorts of great features and UI wins. I wonder how long it will take for plugins to start adopting it.

Is this something that only neovim had? My suggestion plugins in nvim pop over just below the cursor.

Yes, it's only now a feature with Vim 8.2.

Edit: Or maybe only "officially" now with the new floating window API instead of having to roll your own code.

In any case I really appreciate what Neovim is doing to push Vim into adding features. I hope one day they converge into a single tool.