Crowd control. This is an excerpt from an earlier post of mine: Dragon's Breathe is awesome for crowd control on Crota's End. Finishing off the swordbearer with a DB rocket leaves a solar flare which enemies refuse to enter. This means that whoever is picking up the sword never has to worry about cursed thrall attacking from around a corner. Want to make killing the deathsinger easy? Pop three solar flares in the middle room to clear out all the adds and keep them out. Everyone go in and shotgun/fusion rifle her ass. What's that, you're trying to keep the bridge up from the other side and a gatekeeper is owning your ass while you wait for the sword guy to come across? Jump straight up and shoot a rocket below you. Now watch as the gatekeeper cowers from your flames. Gjallahorn is awesome, but the crowd control offered by DB in conjunction with AoE grenades is incredible. Always nice to have at least one guy on the team with it.