I see a lot of people worry about "what if the connectivity breaks," but truth be told, I had a lot more fuzz with physical money than digital. I put away a small sum as a contingency for exactly this scenario that I never used, and in fact, I had to go change that money to new bills because they became outdated. It's the same for my spare change; all the coins I accumulated over the years are now invalid. This could be seen as the physical equivalent of connectivity problems, and as far as I can tell, it happens a lot more frequently.