As an American, we have the same names for the same types of potatoes and cooking methods. I have no idea what OP is on about.
If I ordered a baked potato in a restaurant and did not receive an entire, whole, skin-on potato, optionally sliced open across the top, I would be shocked and would have a negative opinion of the restaurant.
We make roasted potatoes all the time, much like you describe. When we do it at home, we'll frequently use Idaho Gold potatoes that do not need to be peeled, and we'll skip the parboiling step. Plenty of places make this without skipping those steps, and they're delicious, just more labor intensive.
I mean, sure, but there exist some recipes where the inclusion of a thick potato skin is not appropriate, and a russet potato ought be peeled if that is the variety of potato being used. A thin-skinned potato like the idaho gold can sometimes be used in these recipes without peeling.
The russet skin would of course not render the dish inedible, but the final result would be much more different than what the recipe was trying to achieve.
"Need" here means "required to yield desired final product" not "necessary or else you'll die".
If I ordered a baked potato in a restaurant and did not receive an entire, whole, skin-on potato, optionally sliced open across the top, I would be shocked and would have a negative opinion of the restaurant.
We make roasted potatoes all the time, much like you describe. When we do it at home, we'll frequently use Idaho Gold potatoes that do not need to be peeled, and we'll skip the parboiling step. Plenty of places make this without skipping those steps, and they're delicious, just more labor intensive.