It can do SSG while letting you use any framework you want. You don't need to use React. That's a pretty big difference in a thread where people complain about churn.
Personally, I don't see Astro as a must have because SSR + Interactivity can be done with a lot of tech. PHP, C#, etc. But it has a lot of sane defaults around markdown and static generation that I can recommend it.
That's exactly the Turing tarpit argument.