I say unusual in the sense of Japan seems to be the only one to have solved the issue of how do you transport 2 kids on a bike not with "big box" like the dutch and subsequently the entire western world but via 2 seats, they're apparently very popular over there as a means of transportation.
"it's really not that bad" well then explain why I tip over after three seconds on a bike then :thonk-cri:
Lack of practice, you can do it!