Sushi on a conveyer belt

I don't remember having my sushi like this when I lived in Japan as a child, but this afternoon after church I went out with a friend to have some sushi for lunch, and the way the sushi came was on little plates marked with different colours for different prices. I still managed to rack up about 8 dollars. It was fascinating to watch the plates go by on the conveyer belt. I was so mesmerized that I almost forgot to eat. I've seen the plate concept for Chinese dim sum, but in Chinese tea houses dim sum doesn't usually come on conveyer belts. Of course, in that case the food has to be kept hot, and maybe it's not as efficient a way to use energy to try to keep food hot on a conveyer belt.
In terms of revenue, I think this is a easy way to make customer spend money, because while each dish doesn't cost a whole lot, you usually need to eat several dishes. I had 5 plates, and could probably have had more except for the cost. How many people are adding up prices in their heads though?