Lets image a world, where the main feed would not be sorted by creation date, but by the time the client received the note. If the client doesn't have to list the notes by creation date, the client gains the ability to schedule retrieval of new notes, basically setting up short-term subscriptions for X relays, then e.g. 1 minute later for Y relays, then for Z and so on. This could be a tactic to avoid having 100ths of parallel open sockets.
What would be the tradeoff from a UX perspective? You loose the ability to know where to find the most recently created notes, but does that actually matter? You gonna miss out on most notes anyways, unless you are a 24/7 doom scroller 😁.
The other tradeoff coming to mind would be if you wanna read the replies on a note, you have to wait until the client went through all relays... Unless we find a way to somehow tell the client where to look for the replies of a specific note 🤔.