it's the same as right now there are still people that refuse to use credit card or new services...
Credit card have become a usual thing nowadays and most people are already using it. Even commoners or people that live in a not-so-developed place, they know the use of credit card and debit cards since it's not that hard to understand. Let's say that mass adoption has happened. The average joe will eventually adopt to that but there will always be those that don't really want to accept change. It will take generations before the new currency totally takes over and that's when the new currency has become the normal thing to the world.
Only a few thousands of people used the system in a 2-3 years time, so both parties decided to stop the whole thing. Technology is available, it was working fine, but the demand for this kind of fintech innovation was not enough to get it profitable on the long run...
People needs more time for these kind of changes.