Typically it’s for some kind of frequent buyer/rewards program. “Get a free meal after you buy ten” kind of thing.
Most Americans don’t really consider their phone number or their email address all that private. (Or else they’ll have one that they give to strangers and another they reserve for family or close friends.) Definitely not the same kind of “personal ID” that a driver’s license or Social Security number is.
“Majority group” Americans – white, straight, nominally Christian, politically moderate – tend to have a fairly benign view of their government. To the extent that they’re even aware of the ways that state power can be and has been abused, they’re not terribly concerned that it will be directed at them.
(Yes, I know that members of American minority groups have very different experiences. No, probably this is not the venue to discuss the failings of the American government in detail.)
Nor the governments/politics/religions of any other countries/peoples either.
@66meyers: Phone numbers are not a unique identifier of a person, from cradle to grave. And the US has long had directories of phone numbers. Have you heard of the Yellow Pages, the numbers, addresses, etc. for businesses? And the White Pages were for residential numbers. So this is nothing new to the American public. In fact, people will have many phone numbers in their lifetimes. Whether to give a business a phone number is up to the individual, but it’s not required to make a purchase.
Now if any service asks for your Social Security Number that would be highly suspicious outside of very specific interactions as the SSN is a unique identifier for one person for their lifetime.
Back in the 1990s, one of the first policy changes inspired by digital privacy concerns was the replacement of SSNs as driver’s license and medical record identifiers. These days it’s really only needed in banking and employment contexts.