Because it means something different. If I use my phone to call someone, I used my phone. If I somehow create some complicated system where I call someone with a cardboard box, I utilised a cardboard box to call someone with. It means you did something, different outside the norm.

It also means to use something in the most effective way, to get the best out of it.

No one made up a new word, utilise is as old as use, it's just that people are thick and use it wrong