On the language level, Julia isn't statically typed, and it doesn't have ruby syntax. On a tooling level, binaries are easier to deploy than the whole julia JI

On the language level, Julia isn't statically typed, and it doesn't have ruby syntax. On a tooling level, binaries are easier to deploy than the whole julia JIT and your whole source code. And crystal has dynamic multiple dispatch. It's used a lot, it's great.