I can't speak to the second point, but to respond to the first: it's very well suited. I've built two primary compiler projects targeting JS, a Python->JS comp

I can't speak to the second point, but to respond to the first: it's very well suited. I've built two primary compiler projects targeting JS, a Python->JS compiler and a 6502 emulator that dynarec's to JS. Both were easy to build and its flexible nature made everything work out very well. I dislike writing JS myself (just don't dig the syntax), but writing compilers backending to it works out quite well.