You don't NEED to do homework per se
IF you can ace the exam..
You can work out a deal with the teacher..
The system isn't as rigid as it seems, their goal is not to waste your time..
But, i suppose most young kids wouldn't see it that way.. and parents are not involved enough to care..
This is
not universally true. It depends on the class, the teacher, and the institution.
I was a rather anti-authority teenager (weren't we all?

) so I was not afraid to question my teachers and call them on their crap (I do regret this now, btw, as I've learned there is almost always more to it than meets the eye). My french teacher would assign homework that wasn't particularly helpful or useful, so I questioned why we were doing "busy work". She agreed that it is busy work (useless and time-wasting by definition), but would not budge on requiring it. I was of course an idiot and didn't do my work, and almost failed the class.
YMMV
¯\_(ツ)_/¯