Money greases the wheels of exchange, and thus makes the whole economy more productive. The idea that everything should be cashless is problematic for so many reasons. Bartering is a good under certain circumstances and societies, but it relies on what Keynesian economists call a “double coincidence of wants,” making it less desirable than cash.
Cash is easier because it is a convenient medium of exchange, sometimes free from government prying eyes, a unit of account for quoting prices, and a store of value as long as the trust in government is not eroded and inflation is low.