Not quite, it’s still a VM. And while it supports virtio balloon for growing RAM, it doesn’t yet support releasing that RAM back to the host. And there isn’t a convenient way to shrink the sparse disk images as they grow yet, either.

Exactly what I thought. The Mac equivalent to WSL. Which is a great thing for Mac devs. Lots of stuff expects Linux these days, not POSIX. Mach isn’t Linux.