[z3t4]

The startup penalty is because you have to run the VM itself. After all optimizations there is really no benefit in having the code in binary.

[randombytes6869]

Parsing minified JS takes up quite a bit of load time for most sites. Binary formats for VM languages aren't just smaller, they're many times faster and easier to parse and verify

[z3t4]

There are two schools 1) Load everything statically, then run the app 2) Just load enough to show the start screen, then load the rest when needed or in the background. Only the first school would see a significant speedup. eg 30% of 3s vs 30% of 30ms. I wonder however if you would be able to pre-optimize? I guess not because JS is a dynamic language.