Well at first glance the pawn and character pawn are the same except that the character pawn includes a character movement component that a simple pawn does not.
The movement component is very important if you plan on network play as it is the state of the movement component that manages the replication requirements, error correction, and you can plug a function directly from your input table so if you have W set up to move forward the forward velocity is replicated to the connected clients and not the event of pushing W as an action. The movement component also does a lot of other client to client requirements but if you need multiplayer abilities then the movement component of the character pawn does all of the replication requirements for you with out having to duplicate the same requirements using a pawn that does not have a movement component.
Easy to test by setting up for local two player server and if your object aka player does not move then the required replication is not being sent.
Why not use a character pawn.
If you object does not have replication requires then a movement component is not required and one last thing that needs to be calculated.