This is bad news for a lot of reasons, not the least of which are the ways it would affect day-to-day life.
Here's my definition of a cashless society, so we're all singing from the same songbook:
Cash would no longer be legal tender, therefore you could not make purchases with it, pay bills with it, or spend it in any way. You would not be able to deposit cash into your bank account so you wouldn't be able to accept cash for an exchange of goods or services.
Therefore, cash would be nothing more than a worthless piece of paper. (I know, I know. Debt-based currency is a totally different article though.)
We're heading this way. Jose recently wrote that Venezuela is rapidly becoming cashless and here in the United States a concerning early sign is that there is a "change shortage" which is causing many stores to give you your change on a store loyalty card or invite you to donate that change to some cause.
Think of all the times that cash is an appropriate gift. I've always given money, like stuffing a child's birthday card with a $20 bill or giving a new graduate some cash to put toward college expenses. When I got married, we received quite a bit of money from various loved ones. My dad always gave my daughters some spending money of their own each time we visited and they were surprised and delighted every single time.