Yeah. I don't have Barriss, but I've got Luminara to 5* now, and that shared portion of their leader ability - the 4%/2% heal - really starts to add up if you keep them levelled and geared. Not so much for the Arena, maybe, but it's totally clutch in Galactic War; trick is to take out their tankiest char last, so your guys get a couple of turns each while you finish them off slowly. That way everyone heals back up, your cooldowns reset, and you're fresh (or close to it) for the next encounter.