For the less financially savvy amongst us, I think it was just a good incentive to buy a bike that wasn't going to be more hassle than it was worth and put us off of riding for good.
I doubt I made much of a saving on mine (but being less financially savvy I've never actually bothered to try and work it out) but it was relatively hassle free and being a financial doofus because the money just disappeared each month before I saw it, it barely felt like I was paying for it. If I'd had to do the graft myself, I might just not have bothered (although I was pushing myself on the 'get fit' thing as well so that might have been motivation enough, we'll never know.)