Opensource

It's a different use case - bottles is really good for playing games outside of steam (like pirated titles or non-steam games) since it has sandboxing + you just drag and drop the game folder, then add executable as shortcut and run without having to fiddle with paths and set up each game individually. Convenient for software too that runs better on proton too.

If you don't do/have a need for any of that, then you don't need bottles.