Re: analogue backup
"Seriously for many year in Italy (it the time of the Lira) sweets were given as small change"
That was due to lack of coins in circulation ... I remember holidays in Italy as a child when there were want amounted to 10p notes in circulation ... these had no legal standing but amounted to IOUs issued by shops which everyone started accepting as cash. (Interestingly I think a more "official" version of this sort of scheme is what the new Italian government seem to be thinking about as a way to escape from the Euro without having to actually leave it)