I too am one of the folks who have been burned in the past by "auto-magic optimizations" and, in general, refuse to permit any of them when given the option. I will say, after using the NVIDIA app for a month or three and the GeForce experience before it, I haven't really ever used their first automatic guess at what I'd like. Rather, I usually end up ratcheting the quality slider all the way to the right and letting it try again, and I'm typically happy with the result.
I think part of the reason automatic optimizations aren't a great idea is because each customer has a different perspective on what they find important. I can be using the same hardware as my brother, and he'll want >120FPS and I'll prefer something between 60 and 100 with a lot more visual fidelity. Which one is most correct?