Cash use is about on par with most other countries. Credit cards & mobile solutions are slowly rising, but cash is still widely spread and necessary in some cases (like paying for public transport in certain cities, etc.).
In Spain where I am based now, and in New York where I spend a lot of my time as well, I always have a bit of cash on me because small purchases have to be made with cash.
Just spent 6 months in the US and we in Denmark are way ahead in regards to a "cashless system".