So yeah, US contactless usage is still pretty low compared to much of the rest of the world, but at least
Visa is putting out numbers now.
In the Big Apple, 45 percent of in-person card transactions are contactless. The city’s subway and bus system began accepting contactless payments on a limited basis in mid-2019 and in full by the end of 2020. This isn’t the only way to pay for train and bus rides in New York, but it has been much more popular than officials anticipated.
...
In San Francisco, Oakland and San Jose, more than 30 percent of in-person card transactions are contactless, Visa says. The ratio is above 25 percent in Los Angeles, Seattle, Detroit, Miami and Salt Lake City.
Anyway, they don't specify numbers for other areas, but it doesn't seem like transit acceptance is the only factor ensuring adoption. At least around here, I have seen it getting used more often, but I would still say it's maybe a bit less than 20%?
Also probably not a surprise from the article: people seem to be tapping cards more than phones.