Since I got the ‘Most visited link’ notification, I was looking at the code to give a better answer than my previous one.
Firstly, you are completely right.
I believe it is to make the programmer’s intention explicit.
The documentation says:
ROLE_AutonomousProxyThis is generally only used on actors that are possessed by PlayerControllers. This just means that this actor is receiving inputs from a human controller, so when we extrapolate, we have a bit more information, and can use actual human inputs to fill in the missing info (rather than extrapolating based on the last known velocity).
And:
The Actor is a remote proxy, that is capable of performing some functions locally, but receives corrections from an authoritative Actor. Autonomous Proxy is usually reserved for Actors under the direct control of a player, like Pawns.
In which case could this be used? I didn’t think about it but even if ROLE_AutonomousProxy was used on another actor that is not controlled by the Player Controller there would be no problem.
The definitions in the code:
// Owned by connection's player?
UNetConnection* OwningConnection = Actor->GetNetConnection();
RepFlags.bNetOwner = (OwningConnection == Connection || (OwningConnection != nullptr && OwningConnection->IsA(UChildConnection::StaticClass()) && ((UChildConnection*)OwningConnection)->Parent == Connection));
RepFlags.bNetSimulated = (Actor->GetRemoteRole() == ROLE_SimulatedProxy);