Why not have fun and start experimenting? I healed in my static, but when we had member changes and were waiting for people to catch up, I'd take my PLD into endgame raids and try tanking it. Our tank would DPS, someone that normally didn't heal would heal, etc. Not only was it a fun and refreshing change of pace, but it meant we also understood what our friends were going through better than before. Everything you do in the game doesn't have to be to get something, just experiment and goof around.