That startup time is probably the biggest turnoff for people seeking to write lightweight scripts in JVM languages. If your script's runtime is 100ms after a 5 second startup, it doesn't particularly matter if the machine code version runs at half speed.

Of course, precompilation is usually a big turnoff for those same people.

but it is precompilation of the core library, not the whole app, so presumably it could be done only once for the system and cached somewhere. (maybe like .Nets global assembly cache, which caches jitted dlls)