Really, the ideal benefit of this is to get people out on bicycles. They'll have fun, they'll get some exercise, and they'll increase Shimano sales, which, in the end, is what this is all about. I think Shimano contracted with Trek and other traditionally middle to high end manufacturers (Pacific, Schwinn, etc. being the low end usually) because those other brands make their own component parts and aren't associated with quality. It's hard to imagine Shimano or Campy branded components on WalMart bikes - not only that, but WalMart techs wouldn't likely know what to do with those things.
If I see someone "Coasting" with a flat, I'd help 'em fix it. The whole thing here is ideally to get them on bikes. Hell, I'm not (yet) what I like to call an "insane bike person." I do my own repairs and maintenance for the most part but I realize others do it better, and when I see someone fly by me on aero bars with their sleek crotch-gelled bodysuits I am impressed and envious and at the same time overwhelmed.
I'm a student, and for every "good" bike I see, I see 20 more "low end" bikes. Most of the cyclists around here cycle for utility - you can't drive to class and walking is slow, cycling is the way to go - it's how I started cycling and it's why I got my first bike from the LBS rather than WalMart; I wanted something I could really cycle on.
So coasting isn't a bad idea per se, it's a clever idea if they can get it to market. The problem in my head is that if I'm going to buy a $500 bike, I'm going to buy an entry-level Trek or something that will give me good performance. Then again, I might be a bit more technically minded and I love being a mechanic, so there it is. If they had a price range around $200, they'd be in business, but the problem there is that the components alone are worth more than that. An autoshifter is quite a cool bit of technology and requires a (simple) computer to run. That costs money.
In my head? The better way to have gone about it would've been to promote single speed utility-type bikes that are mechanically simple, not in the engineering sense but in the "my little sister can fix it with a wrench" sense, durable, and comfortable. But then, another company would have to do that, not Shimano - because Shimano makes performance pieces and those are neither cheap nor mechanically simple. So there it is.