There will always be a player controller for each player. It’s how the engine identifies which player runs which character, and which remote computer a particular command is coming in from. You can’t avoid this – it’s created for you.
That being said, you could probably build a multiplayer game that used the pawn objects for input decoding and replication, but you’d have to build a bunch of work that the PlayerController already does related to tying particular sets of inputs to particular Pawns and forwarding them to other players – it’s a lot of work (and possible bugs!) that the engine already solves for you.
This is for networked games: Yes, you are much better off understanding and using the Player Controller construct.
For multiplayer split-screen games, it’s not as necessary – you could just wire all the inputs for the different local playercontrollers into each separate Pawn. That could work. I wouldn’t, but it could be done.