Yes I agree! Putting real stones in a vending machine is a great idea to teach kids about geology/mineralogy.
What I don't like are vending machines that dispense molded plastic and then has the gall to refer to them as real minerals...like this one I saw:
Photo #519
Piebald ball python hatchling pre-first-shed.
Stone is a large chunk of tumbled/polished agate with a large crystallized water band in the center (from the Northwest USA).