As others have noted, seems reasonably similar to LiveView, Livewire and Blazor. I’m somewhat bullish on these approaches - server side rendered monoliths (Rails, Django, etc.) are SO productive, at least for the first few years of development, but lack of interactivity is a big issue, and this solves it well.

However, another big issue is the dominance of mobile. More and more, you’ve got 2-3 frontends (web and cross-platform mobile, or explicitly web, iOS and Android), and you want to power them all with the same backend. RESTful APIs serving up JSON works for all 3, as does GraphQL (not a fan, but many are). This however is totally web-specific - you’ll end up building REST APIs and mobile apps anyways, so the productivity gains end up way smaller, possibly even net negative. Mobile is a big part of why SPAs have dominated - you use the same backend and overall approach/architecture for web and mobile.

I’d strongly consider this for a web-only product, but that’s becoming more and more rare.