To your first question: for me it's a on-paper vs reality difference. On paper you're exactly right re "vm created from a bunch of script commands" will end in

To your first question: for me it's a on-paper vs reality difference. On paper you're exactly right re "vm created from a bunch of script commands" will end in the same state. The reality is that once the VM is built there is the temptation/opportunity to make ad-hoc changes for any variety of reasons. Those ad-hoc changes sometimes make it back into the official build process, but sometimes they get forgotten in the heat of the moment. With docker you can't do this...to make the necessary change you are also changing the official build process. No opportunity for the two to deviate. Second question: Yes, that is my understanding (though not a use case I have atm).