When I was stationed at Camp Pendleton around 2003-ish, one of the barracks I was at had a pizza vending machine. It made cheese pizzas (maybe pepperoni too, but I am not sure) that were a little smaller than a frisbee and cost around $5 (at a time when the priciest McDonald’s value meal was almost $5). I never had any myself, but it did take a couple minutes to make and (if I remember correctly) the crust was mostly pre-made. Being able to watch the process (a crust drops onto the conveyor, a robot puts the sauce on, another robot puts the cheese on, another robot puts the toppings on (if any), the pizza is conveyored through the oven) would help occupy the customer’s time. If the crust is pre-made, you’re really just broiling the cheese and toppings to get them melty and hot.

I don’t think the pizza was too tasty or popular, but it was a convenient option if you were drunk.