It wasn't technical aspects of VMs per se, it was how to use them while still keeping things separate. If I had my personal machine as a VM on work baremetal, then in principle the personal VM wouldn't really be isolatable from work because if they had a keylogger then it would capture all input.
Edit: To be clear, I don't think that my employer uses keyloggers. But if the purpose was to keep personal and work separate, I didn't think a personal VM on a work machine really provided enough separation.
I didn't carefully investigate the reverse (having my work machine be a VM on top of a personal laptop) partly because MacOS is easiest for a work machine and I didn't want to mess around with trying to run MacOS in a VM.
> This sounds extremely trusting towards your employer, and puts you at a lot of risk depending on their policies and philosophy.
That's exactly why I didn't go down that route.