Why? I'm quite curious. There aren't any good benchmarks on the internet, especially ones comparing it to other languages. I'd love to actually see some real numbers showing how far off it is from Java or Go (I don't doubt it is slower than Java or Go, as it is a much more sophisticated language).

My anecdotal evidence suggests it is not as slow as many think. It compiles a 500k LoC (that's count of all code in dependencies) project in ~10s on my M2 Pro.