Comment by throwaway17_17

I think your statement about familiarity is spot on. One of the ‘promises’ of the early functional language efforts (late 70s through mid 90s) was that the invariants made it conceptually simple to have a magical, super compiler take the code and produce binary executables that would surpass imperative languages, due to the aforementioned Pandora’s box effect of the non-functional constructs. Universal value semantics are similar, especially without leaky abstractions allowing “please just let me crack the box, I’ll be good and won’t abuse the power”. Commitment to the invariants, in this case purely (logically, at least) value semantics across the entire language could produce executables that approach low-level, less restrictive code results with a much, much lower burden on the programmer.