Why we cannot use DrawDebugString on NM_DedicatedServer?

I’m going to draw some debug string on multiplayer,
but I noticed DrawDebugString function contains a condition “if (GEngine->GetNetMode(InWorld) != NM_DedicatedServer)”

Why we cannot use it on NM_DedicatedServer?

Hi! NM_DedicatedServer states that current application serves as Server. Because of that it has no any UI to show something to players. All that stuff is actual for clients.

Thanks a lot, I thought (GEngine->GetNetMode(InWorld) == NM_DedicatedServer) on the client when multiplayer.