There's some private school in the US doing this to reward children for studying (Alpha school I think?), despite it being one of the most unpopular educational policies imaginable — down there with paddling and forced child labor, to great effect.

If you have a computer system for realtime student performance tracking (replacing stressful tests with frequent auto-checked exercises, spaced repetition etc), you can gamify and incentivize the hell out of it, and to a child, $1 a day is a whole lot of money.