That's not what jfbastien is saying. The point is, until the time when WebAssembly has a GC and a JIT, many dynamic languages simply won't be able to target Web

That's not what jfbastien is saying. The point is, until the time when WebAssembly has a GC and a JIT, many dynamic languages simply won't be able to target WebAssembly (unless the dynamic language developers create their own bespoke JIT/GC), so you may as well stick to targeting JS. At the point at which WebAssembly gets a JIT and GC, then the situation changes.