Exactly! If I’m not buying gas for the lawnmower, I don’t know how much I’ll need to fill it…and the way traffic is around here, I don’t want to leave an extra 10-20 minutes early for work to accommodate an extra trip back inside for change. It’s nice to not have to deal with the cash vs credit pricing much. 
Triedaq, your situation sounds like nothing other than a lease. Most leases are for 3 years, and you do pay a lesser interest rate than if you had financed a sale for 60 or 72 months. Your deal was to get lower payments (for a shorter period of time) than if you had leased the same vehicle; after that, your situation is just like a lease.
Barkydog, my take (opinion only) is that the cash price was lower because the financing agent (whether the dealer or a financial institution) would be at slight risk of default for the length of the term with the no-interest financing, whereas the lower cash price was offered so the financing agent would assume no risk whatsoever.
@Dakotaboy. It wasn’t a lease. I went back to our financial records. We made large monthly payments over the time period, but at the end of the period, the car was paid off. I had investments that were doing well so I wanted to keep my money there. I haven’t been able to get a deal like that since, so I just pay cash for the three minivans I have purchased since that time. Had this been a lease, at the end of the time period I would have had to surrender the vehicle. I was in error when I said there was an amount due.