You could paint this as "rewarding good students", but it's also just as likely to punish students in situations beyond their control, or in situations which aren't ideal.
As someone who had to juggle a full-time job, in high school, and occasionally overslept and missed classes, I can't imagine the frustration I'd have felt at, despite good faith attempt to make my life work, being punished monetarily for not doing better.
One of the reasons I dropped out was that, despite my 3.7 GPA, my attendance record was a constant source of friction with the administration. It was exhausting having to jump through hoops, get lectured, and be treated like a poor performer all because, in my opinion, I didn't have a family that could support me while I focused solely on school.