Are scopes worth their complexity?

[Sainan]

The only reason for scopes I can see in the proposal is to guide dead-code elimination, but surely this could be handled in other ways such as a 'keep alive' section.

Now, on the other hand, scopes impose a decent runtime cost, and also seem to limit the usefulness of func.new, e.g. what if I want to reference previous 'JIT'ed functions in subsequent 'JIT'ed functions?