But seriously, why not put a bag or box in your car, put the groceries from the shopping cart in there and then carry that bag from the car to your home?

@OP When you have continue session on, closing Firefox using burger menu->Quit restores all windows. I assume this will also keep the pins even without continue session.

Nope, this feature has existed forever. They just changed the shortcut, previously it was Ctrl-shift-T for re-opening the last closed tab and Ctrl-shift-N for re-opening the last closed window.