Uber isn't a cash venture, and several activities in the US require either a credit card upon which temporary authorizations can be placed, or a full (and sometimes, over-)payment on a debit card, the difference being that the debit card isn't backed by a line of credit that becomes due in at least 20 days, but rather it is spent directly out of a checking account.

You need this for:

- gas stations

- hotel stays

- car rentals

- sit-down restaurants or bars

The SV/HN is out of touch argument doesn't fly here. Rather, there is a wide gulf in the spending ability and access to services between a US credit card owner therefore a participant in the mainstream banking system, vs. someone with only a checking account, vs. a person who can't qualify for either and conducts their affairs with cash. This is a problem much older and much more foundational than the Bay Area vs. everyone else and the techies and non-techies divide, and is a significant delineation between the US middle class and lower class.

Truly reliable and useful public transit is a luxury in the United States that isn't available to a huge majority of the country.

Walking also isn't an option for many people due to safety, health reasons, scheduling, childcare needs, and not to mention just too much stuff to carry.