"I was always looking for why rocket propelled grenades are so addicting! I can't get enough of the explosions!" Because everyone loves to throw a good AoE blast on a dense pack of enemies!
For the story, TMW recently introduced an AoE ability "The Orb" and players went crazy with it. I ran an extensive test for a GM/Dev to show how OP The Orb is. He then nerfed it. But everyone keeps using it even when it endangers the whole party in quests that would be safer without Orb use. Players with the Orb are like puppies getting lose on a walk, turning stable situations in chaotic frenzy. These situations bought new fun to the game.
Conclusion: players love AoE spells / attacks ! Make sure you have some in your RPG and test them extensively to achieve a good balance.