Check the 2nd section of article https://github.com/clawkwork/clawk#why-a-vm

A lot of people would yell "docker isn't secure!" but if you're running Docker on MacOS (and Windows, I think) you're already running a Linux VM. But if you really wanna let your agent YOLO their way along, Docker is kinda restrictive, so that a full VM lets it install things, start services, and so on.