There's another disadvantage of "too-sharp" edges. The stubble comes back spiky like it does with a DE. Wifey doesn't like that. "Slightly dull" edges produce stubble that comes back softer, not so scratchy.

I have a theory as to why this is, based on the theory of sharpness being a combination of penetrating resistance (determined by the edge width) vs cutting friction (determined by teflon/polish).