(who knows how much damage I would have done
if I was using power tools!)
Potentially a LOT more damage if you "goofed".
Making "goofs" with power tools and sharp objects can be SERIOUSLY bad - primarily for your own safety. But, yes, you can ugly up a knife or damage a knife as well.
I don't want to down-play the "potential" dangers of sharpening knives with power tools. The combination CAN be dangerous. So, fair warning and don't blame me for anyone getting hurt.
But, using a powered belt sander/grinder can be a very effective and way faster means of getting a VERY sharp edge. It is how most pros do it.
.