the idea was more to get that extra bit of speed for profiled bottlenecks. not a need, more a want. benchmark game currently puts Julia on par with go, not rust. also it seems to forgo simd except for obvious cases with large arrays.
I do agree that there a few cases where Julia in theory could do what you wanted, but it's a bit awkward to get the guarantee from the compiler that it will do so (e.g. SIMD this thing, constexpr this thing..). I do hope this situation improves.