I'm using something similar in my game, fate tokens. While they don't do much for roleplaying in themselves, they still add a choice other than the normal drone of dice rolling, and they act as a reward for said roleplaying. Whenever a player does something cool, like good roleplaying, a nice action in combat beyond the normal, or comes up with a good idea, the player gets a token. But obviously these should still be pretty rarely given.
(I use D&D 4E, so some of these aren't universal).
One Fate Token gives you any of the following;
-Can be used as an extra/instead of an Action Point
-Can be used as an extra Saving Throw whenever (But not as a Death Saving Throw)
-Can restore one spent Encounter Power
-Can be used as an automatic Critical Hit/Success (But you have to choose this before you roll)
-Reroll a Miss/Failure/Failed Saving Throw (But not Death Saving Throw)
Two Fate Tokens give you any of the following;
-Can restore one spent Daily Power
-Can be used as an extra/in place of a Second Wind (With the same results)
-Reroll one failed Death Saving Throw