I was expecting it to analyse dependencies and create automated useMemo calls around everything. I mean write regular, readable React code someone might write manually.
It does not do that, instead it creates a cache context. Something like a single useRef object and writes imperative code to check if a dependency has changed, look up the previous instance of a variable from the cache and use it etc. Also caches JSX segments and stuff.
This would work much faster I guess and would be easier to extend.
I assumed the svelte / solid / vue way of reactivity was the way forward for granular reactive apps. Avoiding unnecessary rerenders etc but the React compiler does a really good job and you get all the fine grained reactivity benefits for free. Without thinking about it in the code.
Optimizing compilers are neat.