Earlier quoted context omitted.
I wouldn't say they're ancillary, most of what you said is the claimed benefit of homework (regardless of the correctness of that claim). I'd say you're mostly using the homework as a guide for tutoring, which isn't something that actually requires homework to be assigned by the school if you're willing to be proactive.
Some parents need a little nudge to support their children's education beyond "school is daycare while I work".
Thank you for being a case in point. It doesn't matter what else I do, (see http://bentilly.blogspot.com/2012/10/my-sons-flashcard-routi... for example), I can always be accused of being lazy from the peanut gallery.