Food culture in Japan that I'm curious about.jpg

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Why do they serve it covered up like that? They don't even mix it, so it would be much easier to eat if they just served the ingredients on a separate plate.
It's quite a hassle to scoop up the rice by digging around it to avoid the toppings.
Is this a collaboration between a restaurant's trick to reduce dishwashing and consumers who just accept it without a second thought?
When I first saw it, I wondered if the flavor of the toppings would reach the rice underneath, but after trying it, the answer is no.
I get curious every time I see it.