In Brazil we usually say "X" that is pronounced like "chees" Thats because of the sound of the "e" that makes you naturally smile I guess 🧐

It is the long ee sound that forces a smile. Your mouth has to be in a near smile to make the sound. Cheese is still sometimes used, but some people have fun with it and make up different words ending with a long ee. It could be puppies for example. Of course, the stranger the word, the more likely it is that people will laugh instead.

In Italy we used to say cheese too. However, nowadays no one does it anymore I agree with you, I think that it’s because of the expression of the mouth while pronouncing this word. ☺️