I spent half my childhood in Japan... so I grew up eating sushi. It's like growing up eating sammies. Just plain normal. My son and I eat Japanese food several times a week; udon, tempura, miso soup, onigiri, mochi, sunamono, katsu... and we go out for sushi once every 2 weeks. It's only $10 each for what we order... so barely more expensive than McDonalds.
Kids often have such acute pallets that the veggies we give them straight in western cuisine is often overwhelming to them. As Amanda mentioned... most kids who hate veggies WILL eat veggie sushi or sushi with veggies in them. They're cut fine, often lightly misted with sweet rice wine vinegar, and very subtle. Similar to how a kid who won't touch a salad will eat lettuce, onion, tomato on a burger.