It isn't actually harder. At all. People just think it is because them funny / signs is different from regular math. So they get put off by it even if they're actually good at it because they've built the idea of hating fractions even though it's a very intuitive thing.

You take a string, fold it in half, you've got a fraction in front of you. The rest follows from that basic principle. But when you put it on paper, the only thing that isn't obvious is dividing fractions. Even then, you could figure it out on your own with a bit of thought.

Unfortunately, you jam a bunch of kids in a room and make them do boring things, often being taught by someone that isn't actually good at math, and may have no desire to teach math in the first place, and you get droves of kids that hate math. Someone that likes math, and has spent time playing with it, they'll have a way of translating it into different terms. Instead, you go by the book regardless of if the book works for kids of a given age.

Fractions are just as easy as decimal. You can't imagine how many kids struggle with division in decimals, or even just keeping the number line in mind when dealing with them.

The one belt benefit decimal has over fractions is the ability to write things out by line and do most problems (other than division) in a simple box. That goes away once you're dividing though. Dividing fractions is easier for some.

Also, fractions are easier to estimate with. You can almost always guesstimate what half of a thing will be, so you can almost always keep going until the fraction is too small visually to detect. Eyeballing a tenth of something is not as easy for most people.

Besides, it's good for your brain. It's like a muscle in that regard. If you don't use it, it gets flabby. Flabby brains lead to shitty thinking.