Well yes, you could run your business that way. And maybe your customer lives in a building with asbestos or old lathe walls or another reason not to drill hole

Well yes, you could run your business that way. And maybe your customer lives in a building with asbestos or old lathe walls or another reason not to drill holes in the wall. Or maybe the customer just doesn't want to risk putting a nail in the wall because last time it went right into a water pipe and they had to replace their entire entryway - 2 walls, the floor, and rehang the front door.