What is your opinion on using an LLM to provide immediate feedback/grading at scale such that students have to muster their own answers but can check them quickly, compressing the feedback loop and allowing for more iterations?

Students still have to muster their own answers, but the LLM is used to minimize the confusion or uncertainty about the quality of the answer and the time to wait for that clarity.

My understanding is decades of research long before AI has shown the benefit of timely constructive feedback on the learning process. Why aren't all educators tripping over themselves to use LLMs to maximize access to timely constructive feedback?