Docker for Mac is still running a VM via LinuxKit/HyperKit, but there's a big difference in overhead between LinuxKit and running VMWare/VirtualBox.

Well, in the case of Mac, basically performance, as you still need linux libs, kernel API and everything. But it's much lighter-weight than something like Virtualbox, VMWare, etc.

In Linux iirc, a hypervisor can share such resources with the host system (since they are both Linuxes).