If used properly it is good to clear mobs and also against bosses. Never just save it for the boss, that is definitely a waste. My regular group consists of all three classes, when the Hunter tethers the boss and a group of mobs at the same time and I use my hammers it is a glorious sight, dead bodies everywhere and orbs stacked up like engrams in the old loot cave, then the warlock clears out the next group of mobs so we all have super again. Synergy, communication, and strategy are beautiful things when used properly. Defense titans are useful and have their place, but if everything is dead there is no need for a bubble.