There was a video (which I can't find right now) of a guy wanting to show off his new super duper tactical folding knife, with some high tech steel blade and all. So he tries to ram it into a tyre. But it stops dead after a few mm and instead his hand slips down the blade. He was bleeding like a pig and had to be rushed to a hospital, because he had cut the muscles and ligaments in the fingers. It needed surgery to avoid that his fingers would remain stiff.
Thats how to learn it the hard way...

To the sharpening: I dont use machines, only stones. A portion of blade that is bulged outwards is not much of a problem, but if its bulged inwards it is. The stones are not really shaped to deal with that. Yes, it can be done, but it takes far more effort and time than a regular blade.