Deanna's presence on the bridge makes sense because of her empathic abilities. Highly useful skill for a starship captain to have at his disposal during negotiations/conflicts etc. Same could be said for a telepath. As a captain, who wouldn't want to have that resource available?
There would be little reason for a ship's counselor with no such abilities to have a permanent bridge chair.
One of my favorite Deanna moments on the bridge is when Geordi is on the pakled ship. She warns Riker, that something is not right. Riker ignores her and then she doesn't mention anything more about it. Of course, that would have ended the episode right there.

Very lazy writing.