It depends what the rewards are as to whether it proves an incentive. I'm going to guess online discount vouchers or similar. Yes, as she says, the ones who will be most enthusiastic about it will be the ones already walking regularly; free stuff for no extra effort. My concern is that once again it relies on people having a smart phone and an app and being able to navigate the Internet. Those who might benefit most, eg older people, are least likely to be able to do so.
I do think it sounds like a big effort for what will be minimal return in terms of how many folk benefit but the other ideas offered by the surgeon will require large, expensive, cultural shifts that no government is ready to fund.