Why not pencil-and-paper? Oral is vastly less efficient, and also problematic for ESL and many other types of students.
I remember when I was a kid people would just copy other people’s essays and just reword the sentences. So people who want to cheat will figure out ways to cheat on homework, etc. AI is just the new vehicle.
I think grades should be based 90% on exams, and 10% or less on homework. Homework should be practice not what your grades are based on.