Binding machine or method for a child?

My daughter writes books constantly. She mostly uses printer paper. They are generally 25 pages each. She got an automatic stapler last year for book making and loves it. This year she is turning 7 and I was thinking of getting her a comb binding machine. Are there any that might be easy for a child to use? She’s not very strong. Or is there a different method I’m overlooking? We have tried binder rings in the past and she was not a fan of how the books held together with them.