Once i watched the multiplayer test, i got a little bit of an idea on the usefulness of a banner other than aesthetics.
Suggestions banner should:
Act like torches in minecraft in which, creates a safe haven of distances so mobs can’t spawn near bannered area (although that how it works in single player i suppose, but i meant for multiplayers) especially for pvp multiplayers where each villages need to have a distance (so no early trolling).
Banner as a property maker (as in if a banner is put unto an area, that area will become a safe area for building new settlement).
Settlement with different names (this is just if possible, so that banner is used to name a new settlement just like our start).