In Poland, article 59 of Prawo o aktach stanu cywilnego forbids people from naming their child a diminutive amongst other things.
So unlike the UK and the US (as far as I know) you couldn't name your baby "Jimmy" instead of "James". Or in terms of Polish names: "Kuba" instead of "Jakub".
But aside from that, it's weird for us to use a short name in formal situations. A presidential candidate wouldn't use Joe instead of Joseph like Joe Biden does. You only use it if you're familiar with someone. Otherwise, it's seen as rude or humorous.