It would be very useful if you could either:
Expose COND_OwnerOnly described in this blog post to Blueprints
Make Actor Components have bOnlyRelevantToOwner so that the actor can replicate to everyone while one of its components is only relevant to the owner.
What it would be useful for: imagine a character that needs to have its movement, health and certain other properties replicated. That character can also have dozens of properties that should be updated on server and replicated to the owner (to be displayed in UI) that other players don’t need to know about - max weight, attack damage, attack rate, inventory, RPG stats like strength/dexterity/intellect etc.
Sure, you can update those on the client via RPC’s but it can get really messy once you have dozens of those stats. Since C++ already has COND_OwnerOnly, I’ve tried to expose it to blueprints myself, but failed, I don’t think it can be done without modifying the engine.