There's a bit of HN bias here. Just thinking of the lower income or non-white side of the country. So many people don't even have a checking account (4.5% households or 5.9million )[0] let alone a debit card. There's no way they have credit cards.

While it may be a low percentage number, 5-7million people is not "nobody". Question I would stipulate would be adults vs minors in that number.

[0]https://news.yahoo.com/number-americans-without-bank-account... (households translates to how many people?) [1]https://www.gao.gov/blog/more-7-million-u.-s.-households-hav... (7.1million from April 2022)