Grades allow for tracking progress across many different classes, so that you know for sure where you should spend your time studying. Maybe if this was your only class and you had unlimited time to revise and revise and revise, then this concept would work. It's as if the professor here thinks their class is the only one that matters.
And it's not like this matches up to life after university any better than grades do. Professionally, my task is complete when it meets the needs of the client and I get paid. With this class, tasks are never complete. There's always more revising to do, and you never know when to stop.
The author just seems out of touch. "As for motivation, I asked them, What do you want to learn? Why are you here?" -- this is the same kind of person who asks "so why do you want to work at [minimum wage job]?" as if it has anything to do with the job and nothing to do with needing money (getting good grades).