Because they want your phone number. They are more and more used to link to identities, as people tend to keep (and port) their phone number
Hint: if a store ask for a phone number to get a discount, try the local areacode then 634 5789. This is from an old song, and many people seem to have created "anonymous" account with it!
Hint: if a store ask for a phone number to get a discount, try the local areacode then 634 5789. This is from an old song, and many people seem to have created "anonymous" account with it!
https://en.wikipedia.org/wiki/634-5789_(Soulsville,_U.S.A.)