Yes! Sometimes teachers don't always see things from a child prospective. I've had teachers that went thru chapters so fast a lot of us never understood them. I've had teachers so repetitive on a single subject that we never got through the year complete with finishing even half or text books. Some are hard to understand. Allowing a child to grade a teacher can allow the teacher to know their strengths and weaknesses allowing them to improve.
You may get some valuable feedback into areas the teacher does well and some that could stand some improvement. Obviously you can't trust all the students to be fair and impartial during the grading. But if some areas show consistent trends you'll be able to obtain a fairly accurate idea of the truth.
I gave my students a survey. Not an A,B,C,D,F grade, but specific topics about the classroom, subject, methods,etc. It was very informative, and the kids liked participating in how their class was structured. They felt empowered and respected. (Jr. High)
I am a teacher and I think it is beneficial to have feedback from my students. Of course the grade level of the students makes a difference. I teach special education students K-5 and my younger ones tell me vital information like, "You have lived a long time," or "You look pretty in blue." Lol