AC's online experience sucks in large part because Nintendo is paranoid about item duping. This leads to things like everyone needing to pause their gameplay so the save states can be in sync when someone visits and worse rolling back the state of the world if someone disconnects due to bad internet or their console going sleep due to inactivity.
Given the nature of the game I don't understand why they didn't prioritize fun over protecting against duping.
That's nevermind the fact that two friends can't do stuff like terraform or furnish an island together.
> I don't understand why they didn't prioritize fun over protecting against duping
I suspect they may be aiming for long-term fun over instant gratification. Hard to get items will inevitably have a story attached of how they were a acquired. That means asking about some new thing you see when visiting a friend will get them telling that story. If Nintendo can keep these stories interesting, it’s a compelling reason for people to keep visiting friends in-game.
On the other hand, if item duplication is possible, that destroys rarity, and most items will have no meaningful history to speak of.
A good point about why you care about not allowing dupes, but you can lose hours of gameplay with a rollback[1]. There isn't a periodic save.
This can happen for something as benign as a player taking a lunch break and not babying their switch.
Which harms the long term experience as if it happens to you once, it makes you paranoid about taking a longer term trip to a friend's island and doing something other than a short tour.
Given the nature of the game I don't understand why they didn't prioritize fun over protecting against duping.
That's nevermind the fact that two friends can't do stuff like terraform or furnish an island together.