User blog comment:Mich, Michele & Kuhla/Future Units Preview/@comment-162.228.169.91-20160131002114/@comment-139.255.58.50-20160203042351

NO ! In fact, that effect is worst for Arena Battle even if all units do AoE normal attack. Why ? Because the damage received by enemy is halved. That simple.

It's different case if that AoE normal attack has no any penalty. Or, if Kyle have ATK buff, it can compensate the loss.

If it is AoE normal attack (penalty 50% damage) with ATK +100%, the penalty itself is compensated.