Well, nothing is "needed". But just hitting a button to pause everything is very convenient. I would like it added, just like all those other not-needed things.
This i can understand.

If you just happen to be under the druid grove where the guardian statues are, and they start firing when someone rings at the door. then I don't think switching to turn based will prevent dead partymembers. Or will it ?
Not sure if it will ... since it was buged last time i tryed ...
But it certainly should!
Those statues are suppose to fire once per 6 seconds, aka once per turn.

Therefore you should get single fire ... and that is it, until you end your turn.
