So you have a unique identifier. Your data are stored in a database by the pizzeria to know your address. I think most of the food delivery companies uses this. For example the Wolt (Finland based company)and Foodora (i don't know where is the headquarter, but probably Chinese). All of them operates in Hungary too.

On the other hand for example Google and Apple uses it too. Google called it as advertisement ID, but it identifies you regarding all the information Google collected about you. The do not want to know your name, it's not important. They want to know everything ablut your behavior, about your emotions, aboit your decision. So the can control you, e.g. your decisions, how to vote...

Sorry for this long reply - it focused to #privacy. More precisely the lack of privacy 😕