Both fair points. The README rebuild issue is a Nix hiccup we don't solve; our quantized catalog reduces cascading rebuilds from upstream churn, but input over-specification is still there.
On store bloat: Flox makes it clearer what's in use (explicit environments vs. implicit dependencies), but you still need nix-collect-garbage.
The store accumulates cruft, that's Nix reality, we haven't changed it.