That single (or doubled) convex blade profile is the big defining difference between shears and scissors. There’s some other things like grip sizes and thickness of the blades relative to each other that separate things like tailoring shears and dressmaking shears, but those aren’t nearly as codified. And that’s ignoring all the complexities you get with beauty shears, or the absolute hell that is trying to sharpen pinking or thinning shears, especially if the blade has a nick in it that requires reprofiling. Its fascinating how complex such simple tools have become as we’ve adapted them for ever more specialized tasks.

I think it’s down to most people not having used modern high end shears, which usually have convex bevels (and some pain in the ass exotic steels). If you can sharpen that without destroying the tension/edge finish using a hardware store stone (like someone in this thread was claiming), I’ll be properly reverential.

While pedantically you’re correct, subjectively it’s needlessly misleading to imply that a substance that’s been reduced to the point that it’s nearly a pure element is somehow still the original substance.

You’re highly wrong, then. Go get a straight razor and drag it through some paper, then see how nice it is to shave with. Fabric shears have surfaces honed to the same degree.

Any disruption of the interference fit between the contact or cutting faces can ruin scissors - it’s a lot like grinding a straight razor, but where you have incredibly strict angle requirements across a compound surface. You’re absolutely right though that the #1 mistake people make is to mess up the hollows by flat sharpening them like knives.

Consumer grade whetstones are completely unsuitable for maintaining fabric shears. Maintaining a consistent bevel on stones that coarse is damn near impossible, and you’re most likely going to ruin the mate between the cutting faces beyond repair.

(“well I sharpened mine with an unoiled chunk of arkansas asphalt and they cut even better now”: no you didnt, you’re cutting with the burr, it won’t last, I hate you.)