It detects naming collisions, orchestrates recomputation with a topological sort and manages module reuse and normalizes generators and promise to a common abstraction. The parameter indirection is for separating the inner cell code from the inter-cell dependency graph. You need to do that for the partial recomputation to work without the user manually plumbing in the dependencies (like you have to do in React). I will read the TC39 I don't know it so can't compare.

Edit: yes seems like signals could be a major building block to do the recomputation part