I think there’s some confusion here. From what I understand the system is thus:
The cost of the machine is divided into 24 monthly payments, with 0% interest. Go over that, and the interest rate increases to 20%. It’s basically the same thing you can do with a big TV at an electronics store, and assuming you pay the installments on time, from what I’ve gathered skimming the site basically costs the same as just buying it outright? (Don’t quote me on that).
There’s also the option to “trade-in” your Surface after 18 months for a new model, which presumably would initiate a new 24 month financing plan. Basically instead of re-selling your Surface for a % of the value, you’re saving a quarter off the price, which I guess might appeal to a certain group of early adopters?
I think the big question is I didn’t see anything about the keyboard/pen for the Surface Pro. If those aren’t included, it would seem to throw a wrench into the value/upgrade proposition if you have to buy that stuff and are then stuck with it come upgrade time.
EDIT: Teal Deer version, this is basically the same thing countless big box retailers do, Microsoft is just cutting out the middle-man.