There's no real reason to do so...
Sweden, for example, is bearly usibg physical money at all
The question can be looked at in a broader sense, examining old technologies working in parallel with newer
At the end of the day, the last end-user, should abandon the old tech, for the regulator (in tgis case) to switch it off
sms (or 2g cell networks in general) are a good example
Evantually, the only barrier not to impose using debit cards (which unlike crypto-currency are quite common), is the potential damage for the economy from physical money users.
Regulation can encourage or incentivize traders to move to debit cards, using taxes, fees or subsidies, then when the physical money usage drops, stop generating physical money, with minimal damage