And even if Babel compiled to asm.js, the clever thing about asm.js was that it was valid JavaScript supported by almost all browsers, it just might not be a fast path.

That being said, asm.js in general goes out of it's way not to allocate and invoke the garbage collector, so it's not the best target for other JavaScript anyway.

My point is that you do not need Babel if you plan to target modern browsers anyway.