Power grips are straps designed for bike pedals. If the child wants them badly then I would say encourage him. My latest pedals are shimanos with platform on one side and spds on the other, and I like them a lot, even if they're obviously not quite what a hardcore roadie would use. But being able to ride with one leg clipped in and the other not seems a huge advantage, plus I can leap on my roadbike without having to switch shoes.