Because it'll increase the domain of time that you are frustrated by substandard behavior. Have you used NoA? EAP isn't terribly stressful, you turn it on... if you want to change lanes you disengage, pass and re-engage. NoA for me is just a ton of mental work because not only am I deciding when I need to change lanes it is too and I'm having to negotiate which ones it are suggesting are real and which are completely wrong.
For example yesterday EAP said pick any of the 4 lanes to proceed. But only 2 of the 4 actually would take me to my destination and if I waited until EAP said to change lanes, I let alone it would never make it over across 2 lanes in time. So not only are you stressed about making lane changes, but you have to also add the stress of rejecting someone's very wrong opinion which makes you second guess yourself. "Take the left lane." "I'm pretty sure the right lane is the one that goes through." "Change lanes to the left!" "No! go to the right! Why aren't you going to the right. Oh god, did you just swerve back into the left lane?! I said change lanes to the right that was our gap, I give up let me drive."
EAP used to only work on controlled highways then they let us use it on surface streets. It works fine except it has to swerve over into merging lanes. So now instead of using human autopilot I have to anticipate when it's going to merge, disengage and re-engage every time a merge lane comes up. Things that the human brain can just do on its own autopilot require vigilance and intervention. Or this morning I had to anticipate autopilot stupidity like slamming on the brakes when a car makes an unprotected left in front of me, even though they are well beyond my stopping distance and decision point for an emergency maneuver. So not only do I have the stress of judging a car passing in front, I also have the stress of judging autopilot's stupidity level to counteract its dangerous reaction.