Because you don't have to spam it. You have control over it.
I leave AOE on 90% of the time.
If a mob wanders into range, I sleep it or kill it or stop casting until it wanders out.
If the situation warrants I must continue casting and can't afford the add, I push Z a few times. It's terrible. I lose some sleep crying about it. I write letters to the developers. Oh, no, sorry, that isn't me. I don't give a ---- because it's easy and intuitive.
I'm not asking the developers to change a fundamental aspect of the game upon my personal whims, either. I've adapted to use the system in a manner that works efficiently for me. Start listing ways this would make the game better and easier to use, because I'm not buying the adding 2x the spells to the spell list & action bar a real crowd pleaser. I'm not buying that it will be more tactically advantageous when the situation exists right now. You can AOE or not AOE. You can spam or not spam.
People are insistent on putting more limitations on this game than necessary.
And in-case you don't know, I've opposed Auto-Attack since it was first a hushed whisper. Time will tell what it really adds to the battle or if it makes it stupid, sluggish and boring like XI's battle system was (in my opinion). I don't have big expectations for it, but hopefully SE will surprise me. So far, I'm not impressed.
