I remember my mother ranting on about wasting time on cookery lessons, I could learn everything I needed at home - and to be fair, I did learn a lot at home, particularly things like preparing veg and soft fruit for the freezer, and making jams and chutney, and a lot of traditional home cooking. Did choux pastry and proper swiss rolls at home, too.
My first cookery lesson was to make cucumber sandwiches - this was a revelation to me, because we peeled the cucumber, and cut the crusts off, and they had to be cut in triangles, not squares. Then we had to wash up properly (and I am much better at washing up than my mother was, partly because of school.)
Later, we did fruit salad, which involved cutting up real fruit rather than opening a tin, and making a sauce out of fruit juice thickened with arrowroot - which was a new thing to me. We thickened sauces and gravy with flour or cornflour at home; arrowroot wasn't something I knew about. There is a tub of arrowroot in my cupboard right now, and that's a direct result of learning about it at school. So I did learn things from school cooking, while other things were more from home. And cupcakes I did at home and school. School stuff was usually edible, despite my mother's complaints.
But if you have to do it all at home - well, that's fine if you grew up in a cooking household, but what if you're in a household where no one does cooking? How will they be able to show you how to rub fat into flour or cream butter and sugar together? Where do you learn basic techniques? People in a household with proper cooking are going to have a massive advantage. There's plenty in the press about people unable to cook proper meals, but if you're meant to learn it at home - well, how can you learn if that knowledge isn't there?