Completion is the homework grade around here. In all but math, a child gets at least a B in the course if they hand in all the homework, correct or not.
My older dd (high school) gets completion grades for homework in some of her classes and it does count toward her grade, which I agree might be a way of inflating a grade even if the homework is poorly done. Fortunately, she is motivated to learn and isn't one to just write something, anything down to have it done.
My youngest (middle school) gets actual grades for homework quality and correctness, but homework contributes nothing to your class grade. The grades that show up on her report card are based 100% on her test scores (unit tests, quizzes, midterms, etc.). I'm not sure how I feel about that one. For a kid who is a bit of an erratic test taker due to some rather divergent reading of directions and attention to detail issues, it makes knowing her class grade a bit of a guessing game since how she thinks she did on a test and how she actually did rarely align.