I absolutely agree that the Apple keyboards are overpriced and the reason why I have them all is because I have bought all of them either on sale or used.
I use the Smart Keyboard Folio sometimes when I know I might have to type but not much, and not in the dark, instead of the Smart Folio (no keyboard) or the MK.
I would never buy them at full price.
I got the Smart Keyboard Folio for $60, the Magic Keyboard for $100, the Logitech Combo for $100, and the Folio for $40.
I spent more for the 12.9 got the MK for $230 on sale, but still way less than the Apple price.