It appears macOS native containers runs a separate Linux VM per container.
OrbStack's claim to fame is that all containers run in a single Linux VM, with lots of optimizations on both sides of the VM boundary (including use of a sparse image file for disk storage, which saves a lot of space on the macOS side).
If you run more than 4-5 containers on macOS, the performance and resource usage savings of OrbStack really starts to add up quickly.
OrbStack's claim to fame is that all containers run in a single Linux VM, with lots of optimizations on both sides of the VM boundary (including use of a sparse image file for disk storage, which saves a lot of space on the macOS side).
If you run more than 4-5 containers on macOS, the performance and resource usage savings of OrbStack really starts to add up quickly.