Speaking as a Healer from FFXI and FFXIV, I cast healing spells, buffs etc 99.9% of the time, because that's my damn job. White Mage is a healer first and foremost. In other FF titles, a WHM was there to keep the party alive through the battle. Now, while XI (Where if you as a WHM decided to DPS, you'd be kicked from the party/alliance faster than Pandemonium Warden swatting you to the ground) and XIV are MMO's, that doesn't mean that they should be out spamming DPS spells non stop. All that does is generate massive hate, which the Tank may or may not be able to pull the mob off of you (regardless of how 'good' the tank is).
Now, having said that... against trash mobs in a dungeon, casting the odd DPS spell on SUFFICIENTLY WEAKENED ENEMIES NEAR DEATH to finish them off and allow the others to move on to other targets, Hey... I've got no problem with that. DPS against a boss, that's just asking for trouble... Why? Because you end up using valuable MP which should be used to keep your party alive. But for those who think WHM is a DPS (which by the majority of the posts in this thread DO think that)... sorry, take off the rose tinted pince-nez and wake up. You are a HEALER. You're first and primary role is to HEAL AND KEEP THE PARTY ALIVE. Everything else is secondary.
Flame me if you want... but I will continue to play the same way that served me well in XI and other MMO's here as a Healer.