I'm pretty impressed by all of these systems. We don't do allowances (I would, but none of us can remember). I pay for necessities and activities. If they want something "big" they have to earn it through extra chores--I pay for occasional treats. My kids aren't much into stuff (except electronics) and would not be incentivized by money for grades (don't think I'd do that anyhow).
My daughter will not spend a DIME of her own money without thinking it over for so long she forgets. My son will save his until he has enough for a video game.
I'm sure it would be really good for them to have some of this structure.
