The main benefits right now are tree-shaking, minification, and single (or a few) bundled file caching (browser does that, so it tends to load once per version). Esbuild can build css as entry point without any other config options, I haven’t seen any problem with css building.
It’s worth it for now, browser capability around this is improving (e.g. import map). Honestly esbuild config is really simple compared to js-based bundler.
