Why don't schools allow students to "spend" their grades on indie games?

What’s the overlap between “wants indie games” and “students who don’t work hard on their grades but could”?

There’s a danger that students will see indie games as being “games that aren’t good enough to be worth anything” which could be reinforced by them being given away by schools.

What would the schools get out of it?

If this worked, would it undermine students’ intrinsic motivation and set them up for failure further down the line?

Because grades should not be viewed as rewards, but rather as an indicator that learning has taken place, both by students and teachers.

What you propose is something of a Goodhart's Law violation:

"When a measure becomes a target, it ceases to be a good measure"

Do we want an economy of grades, with all the unintended incentives that would give everyone participating?

This has been done with pizza, and books, and actual cash for at least 30 years. The results of trial programs haven’t been significant enough for it to spread.

My feeling is the affordance students need to succeed would be better facilitated by project based learning goals. Why not give them credit for making games?