90 essays in 2 hours is 1 minute and 20 seconds per essay. Unless they are very short, that's not even enough time to read them. If I spent hours and hours writing an essay and then found out my teacher/professor spent less than 90 seconds grading it, I would be pissed.
I agree with the math, and I'd agree with you if I just did this once at the end of the writing. That's why this works better with formative assessment. The speed of the feedback was actually a virtue for them, and they can use it to reflect on and improve their writing. The feedback is part of the writing process instead of the end of the writing process.
I'd agree with you if there was a correlation between time and quality. there are instructors spending 15 min to an hour grading work and not being assistive in the writing process for students, all the while incurring delays in receiving the feedback. I always say that people's mentality towards AI is rather dismal. AI is the intellectual equivalent of a jack hammer for concrete workers. Much quicker and more powerful, but you need expertise and a level of responsibility to use it effectively. AI is not going to replace the ability to provide constructive feedback as you really do need to know what you are doing. Everyday computers are fascinating and advanced, but they aren't that smart yet.
