Using Medica II between pulls is just a dick move to Tanks and the other Healer it's not something you should be doing but I think some people in old content do stupid things for the hell of it instead of taking it seriously. Though I still see plenty of WHM's in endgame content spamming Medica II when they don't need to. WHM has tons of AoE heals and sometimes a Cure III or medica is a better group heal and doesn't build up aggro.
