Just going to disagree or are you going to back it up with some arguments to why?
Turns does not have to be equal, not even close to it. You simply wait for your turn with the ATB filling up, you can't just mash away. ATB gives more strategy than what the battle systems of FF-FFIII does as well, such as haste and slow playing much more bigger parts.
Turn based, with time as a factor. It could as be turn based were time isn't a pressure and the bars are replaced with an order. If you only count FFX as turn based because of it having order then you are against FF-FFIII being turn based because they go for a special order after you have choosen everyone's moves before any of the characters or the enemy act, they all perform their attacks and the enemy perform theirs and then you choose all your attacks again. With that not being turn based then Final Fantasy was never a turn based RPG in the first place and Final Fantasy has never been traditional since after Final Fantasy III.
But that is also taken in turns, since when the enemy attacks, what can you do to stop it? It is not your turn, you can just hope your stats and buffs is going to make you survive the hit. Seeing how you can't flee the attack the enemy is doing but stand and take the hit and the enemy can't do anything but the same does sound like turn based to me.
But really, turn based games are pretty vast.
There are those with ATB (FFIV, FFV, FFVI, FFVII, FFVIII, FFIX), those who you have to select everyone's moves before they perform it (FF, FFII, FFIII), those where every characters act in an order (FFX).
So, Final Fantasy never was turn based, or? Why is it so known as a turn based RPG when the most known representants of the game to the whole FF fanbase (FFIV, FFVI, FFVII, FFVIII, FFIX, FFX) all use ATB except FFX?
From rereading your post I also see that you don't know about wait. In most FF games with ATB you have the option to use the wait battle mode. That means when the ATB bar have been filled up and it's your turn and you choose any action (like magic, attack, etc) and while targeting, choosing spell, item or whatever it is you are doing every other bar stops, that counts for the enemies bars as well.
And ATB is not real time. Far from it. FFXII was close to real time, you could run away whenever you wanted and you could choose attacks at any time but it cost you time to charge the bar. Devil May Cry is real time, any game with ATB is not. What genre is ATB if it is neither real time nor turn based?