I've never needed accurate fractions, except for one case where I should have stored the width and the height of the image as the original figures instead of trying to represent it as a fraction. But that's not a big issue, there's literally no downside to having width and height of the image as integers.

I see no reason why I would need to represent it as an accurate fraction instead of two numbers, even if I divide it later I can always just do that inaccurately since the exact aspect ratio doesn't matter for resizing images (<1% error won't affect the final result)