I think it's hard to imagine, because every patient must carry a laptop or cellphone to do the transaction, and it might be a little complicated. Compared to bitcoin payments, payment is made by cash only ... !!
You're wrong. People now need smartphone than wallet. Nowadays every single person usually always carry a smartphone when go to anywhere, even sometime they are not carry his wallet when he left. So, this way will make easy for them to pay.
If the patient expresses want to pay the cryptocurrency and the hospital accepts such payments it probably does not matter if he has a smartphone with him. Usually, such payments take place after the end of treatment so it can be done after some time from the invoice. It's just a matter of arrangements between the hospital and the patient.