How do you properly cook potatoes to make mashed potatoes?

I just saw a commercial for some frozen bagged potatoes that you steam in the microwave and then mash the way you normally would, which is what inspired this question. The woman in the commercial is LABORIOUSLY [rolls eyes] peeling raw potatoes to boil them. It’s such a big deal that she has to buy some too-expensive frozen stuff instead.

Now, when I boil potatoes for my potato salad, I scrub the skins, boil the potatoes with the skins on, and then they peel as easy as pie. Yet when I’ve watched people make mashed potatoes, they always peel before boiling. Is there a difference? Can you boil potatoes skin-on for some things, but not others? Or has nobody thought to do it that way before?