Exactly the same thing that was being said when the first ATM's came on line around 25 or 30 years ago. Hasn't happened yet for the same reasons almost. With the original cause of failure to take hold was that they charged for each ATM transaction, even at your own bank. Why would I stop at the outside ATM (i.e. Debit Card) and pay to use it, when I could just walk in, go to a teller or write a check and do the same thing for no charge. It was something that wasn't all that well thought out at the beginning. Now it is more that external machines rely heavily on the humans to be smart enough or mentally tuned into modern technology enough to use them. People in my age group fall into two categories.... those that cannot grasp every part of it (like programming), but, don't have a problem with technology and those that have convinced themselves that they cannot master it. They can use a calculator and a typewriter, but, haven't yet figured out that basically all a computer is would be those two skills on steroids.They seem to want a complete change to have everything digital. Before you know it, there will be no more tellers.
My credit union pays me to use my Debit Card now. 3% on my balance every month when I use it 30 times or more. No limit on how much the purchase is either. Want to buy a pack of gum everyday, it counts. I carry cash in my wallet, but, sometimes the same $20.00 will stay in there for months which probably throws off the money in circulation calculations all off.