In my experience, I strictly see scene2d as for use with gui based things only and not with actual gameplay. Such as for buttons. It does gui stuff excellent.
However for control of entities, actors, players, trees, etc...
I personally wouldn't recommend using it for in-game. Though I know sometimes people do.
I would recommend it for your rpg's menu and overlay(always there) type of stuff.
I had spent too much time struggling with it because I wanted access to certain things that are abstracted and handling the in-game stuff myself was far easier.
just my 2 cents