One thing that comes to mind after reading all the comments, is the seemingly very healthy and lucrative ATM business. Also, in the US, cashier's checks, money

One thing that comes to mind after reading all the comments, is the seemingly very healthy and lucrative ATM business. Also, in the US, cashier's checks, money orders, and sending money via services like Western Union accept cash only. Most? state lottery sales are cash only as well. With these industries and use cases, i lean toward the notion that "cash is king" and will exist as paper notes and metal coinage for another 2 or 3? decades.