just because MC has system he forgot that he can learn things normally like a person. i thing that irked me is he took on guise of uzumaki and wanted to trade info on uzumaki clansmen but never completes the transaction with kushina because of other shiny abilities. he could have traded that information like a normal person and learned sealing from kushina which she was willing to provide him and get acquainted with him. author simply forgot about how to do things like a normal shinobi.

genin naruto kills zabuza with ease in their first encounter with just suicide clone bombings, he doesn't have a single of trait of naruto that makes the manga and anime good.