It can be used offensively, but melee range and necessity to stay in it are quite a crutch. For example, if you try to do that offensively in a battleground, especially epic, you will likely just overextend and get focused. Possibility to pick between ranged, but single-target and affected by GCD stun and melee, but AoE and its delay negating the GCD could still be better and allow to adapt better to different situations / modes.