So sushi and onigiri (rice balls) are similar to a naive eye to me wherein there's some shaped rice.
Sushi usually gets some vinegar for taste and to help it stick to my understanding.
Yet onigiri doesn't? https://en.wikipedia.org/wiki/Onigiri At most the rice gets plainly salted?
I was wondering if there are particular reasons whether for construction, taste etc for the difference in handling. Both can be eaten hand held so my possible theory of sticky vinegar undesired for onigiri doesn't make sense.
Is it a cultural or traditional reason?