I like a nice flat skillet for Multi- Purpose use, especially for frying so that the oil doesn't pool in the center (downward warp/spinner) or all run to the sides (upward warp).
Now if I want to make cornbead, or skillet brownies, or baked stuff, then a little warp up or down doesn't matter as much....
I never knowingly buy a warped piece (unless it's maybe $5 with a planned use).
Just my personal preference.