> Having the islands of actual react stuff is incredibly useful as well.

I've tried multiple times to come up with usecases where they are worth it, but still haven't found any. The only theoretical examples are things where you wouldn't be using Astro in thr first place, like real-time document collaboration or something.

Curious what you've found them so useful for. Besides just preferring React syntax to HTML+TS I guess? But again that seems to go against the point of using Astro.

Well I have a static site generated with Astro that includes parts that still use dynamic react stuff, for example an interactive dashboard / slideshow kind of thing and interactive widgets. The data is baked into the static site but I still wanted the rich interactivity from react in certain places. It naturally grew from an Astro project that didn't need any react stuff, so it was a logical and simple step to add it in the few places it was needed.