[Someone]

Euro coin tracking was a bit popular in the early days of the euro, as it showed how coins moved around Europe (you can’t identify individual coins, but each country has its own coins that can be used throughout the euro zone. Spanish and Italian coins move to Germany and the Benelux faster in summer than in winter, for example)

You can still play that game with new coins, but it’s less f visible now, as most coins are old and those already are well dispersed throughout the euro zone (and, of course, more and more people pay with a card)