I think it would be helpful if there is a mobile data consideration (low data consumption) of Nostr. Perhaps an option feature for clients where users only download 7 days of past conversation and low N network. Perhaps there are other ways
Discussion
There are definitely some caching possibilities. Notes themselves are pretty small but auto-loaded videos and to a much lesser extent images can eat up a lot of bandwidth. It's an important problem because centralization will result if not solved.
That is true
