Honest answer?

1. relay management is a nightmare. It presumably causes loss of notes, notifications, followers list, inability to manage timeline (for instance blocking spammers seems to be useless)...

2. apps lack basics like image and video from device, GIF search, or quote-repost button. some have some, but none has all. Some don't even have a block button.

There is A LOT of development to be completed before Nostr is anywhere close to launching for the normie world. Devs are working and producing at an insane pace, but we're just not there yet.