The selling point is not merely cross-compilation; as pointed out in the other thread, it's the any-to-any cross-compilation for any supported target. With Zig, you get to download the compiler for any supported host target and then build binaries for Linux, macOS, Windows, FreeBSD, and NetBSD. In the near future, I intend to expand that list to include OpenBSD, illumos, and SerenityOS too.