A simple example of this is lists. Not only is it common for a single user to mess up his follow lists because of a lack of consistency between clients or devices, but commonly requested features like...

Nostr can represent data types from pretty much any domain, but it can't actually support all the semantics needed to build any arbitrary system.

It is very common and almost inevitable for a single product to have both lots of category 1 and lots of category 4 and some % of category 2 & 3