I imagine there’s some overhead savings but I don’t know what. I guess with classic hypervisor there’s still calls going through the host kerbel whereas with this they’d go straight to the hardware without special passthrough features?

There is no hypervisor. So, no hypervisor to update and manage.

I recently heard this great phrase:

“A VM makes an OS believe that it has the machine to itself; a container makes a process believe that it has the OS to itself.”

This would be somewhere between that, where each container could believe it has the OS to itself, but with different kernels.