Yeah, I'm pretty sure we just lump your biscuits in with the umbrella definition of "cookie" and some of them are just harder than others. As for our biscuits, I have the same problem that I've never had a scone, so I also remain pretty sure that scones are what I'd call sweet/non-savory biscuits...but I'm also not sure.

The ingredients for American biscuits: flour, butter, baking powder, and milk.

EDIT: trying to make them in places outside the American South can be more complicated than the recipe indicates, though. I read an article a couple of years ago, where someone dug into the problem of why biscuits aren't very good when they're made outside the American South. Apparently, the hardness of wheat flour (which I didn't even know was a thing) is different, in different flour producing regions, and only the softer flours produce good biscuits.

This explains why they're a regional thing. It also explains why I, as a Texan, have had such mixed luck, with biscuits sometimes turning out perfectly, but other times turning out way too dense and horrible. Apparently, we get both types of flour here, and they are not labeled according to which one is the biscuit flour and which one is the bread/roll flour.