Calculators can make decimal easy and fractions hard when doing it yourself fractions are much easier it's an anti-cheat of sorts

Edit: I'm getting a lot of flak for something explicitly stated in a text book, yeah some calculators can but they are less common especially in grade school and it could just be a carry over from time's when calculators couldn't, my point is that this isn't some random theory it's a real thing real text books have done.