I’m not sure why they had the 0% when I bought my JD.  It was already discounted more than I expected and they had an additional discount if you bought two implements.  They had an additional discount if you took the 0% financing for 5 years, $500 as I recall.  I asked for a cash discount instead, nope, you have to finance.  My trade in covered the down payment and we made a payment once a year, so I had the tractor a year before we made a payment.
I don’t know if they hope people miss a payment so they can whack them with a finance charge?