It also affects the learning curve. English-speaking children can read far more advanced books earlier than equivalently educated Japanese.
They probably don't outweigh the disadvantages, but there are some small benefits. Once fluent, I think I remember Japanese to be slightly faster to read because of the more unique shapes. And you can make more flexible and elegant graphic text designs and tables (like in Excel) given the compact words and natural vertical writing.
My children are Japanese-English bilingual and can read far more advanced books in English. Initially I took this as an imbalance and suggested they read the same books (or something very close) in Japanese. But their native Japanese language teachers said, no, because of the different learning curves you can't expect them to read the same level of Japanese texts; the equivalently educated/advanced Japanese reader will be behind, at least in the elementary school years.
Japanese as a whole are extremely avid readers, so I don't think there's a gap at the top, only the shape of the learning curve.
They probably don't outweigh the disadvantages, but there are some small benefits. Once fluent, I think I remember Japanese to be slightly faster to read because of the more unique shapes. And you can make more flexible and elegant graphic text designs and tables (like in Excel) given the compact words and natural vertical writing.