What is more meaningful?

A letter grade with no context, or written feedback/commentary on your work? A dialog around improving your work?

Seems like a far superior concept than simple letter grading.

Also as you get better, the need to revise goes down dramatically. Seems like a pretty good incentive to focus on actual improvement and not just now to get a better grade.

Meaningful learning - after having dealt with "education" I can see why the concept puzzles you.