When you let elementary school children fail constantly at easy tasks because they forgot about them it just instills in them that the grades don't really matter.

Little children need the habit formation brought on by asking if their homework is done everyday, how they're doing in school, and if there are any upcoming projects because they just don't have the discipline at that age usually. As they get older these checks can lessen if they've formed the correct habits. It also emphasizes that their education is important to you so that they realize it probably should be important to them.

Some children form it earlier than others but you're setting your future kid up for failure and being behind early if you think you should be totally hands off with their education.

Also all the other good parents will be ensuring their kids succeed and children start getting sorted out by grades fairly early in their education. Letting them take a bunch of preventable failures early on before they even realize the importance of education, when you do just seems cruel.