The European Central Bank is sitting on a paradox it named itself: fewer people pay with cash, but more people want to hold it. Banknote stocks have climbed from €1bn in 2016 to €1.6bn by June 2026, even as contactless and smartphone payments dominate daily commerce across the eurozone. ECB chief economist Philip Lane disclosed the trend at the MacGill summer school conference in Ireland, framing it as a resilience signal rather than a regression. The drivers are not nostalgia. The 2025 EU emergency preparedness guidance — urging households to stockpile 72 hours of food, water, and cash — was issued against a backdrop of catastrophic wildfires in France and Spain, the sustained cyber-attack that crippled Marks & Spencer's online operations for weeks, and the ambient threat of wider conflict. More than 31 million notes are now in circulation, up from 24 million before the pandemic in 2019. The €50 note is the most popular denomination, followed by the €100. Multiple EU member states — Austria, Finland, Germany, Sweden, the Netherlands — have recommended households keep €70–€100 on hand. This is not a fringe prepper movement. It is official government policy, coordinated across the continent, treating physical currency as critical infrastructure for crisis scenarios where digital systems fail simultaneously. Olive McCarthy, professor at University College Cork, delivered the sharpest framing: "use it or lose it." If cash retreats entirely to mattresses and crisis kits, the network that makes it usable — ATMs, merchant acceptance, bank branches — will atrophy. The paradox deepens: the more people hoard cash for emergencies, the less they use it day-to-day, and the weaker the infrastructure becomes for the emergency they're preparing for. Lane flagged legislation to preserve ATM networks across EU high streets — an acknowledgment that market forces alone are dismantling the physical cash infrastructure even as demand for cash-as-insurance grows. McCarthy also emphasized cash's role in financial inclusion: elderly citizens, domestic abuse victims who need spending independence from controlling partners, and children learning budgeting all depend on physical currency's anonymity and accessibility. The structural tension here is between two legitimate goods. Digital payments are efficient, traceable, and convenient. Cash is private, resilient to infrastructure failure, and inclusive of populations that digital systems exclude. The EU is currently getting the worst of both worlds — declining transactional use undermining the very infrastructure that makes emergency cash viable, while anxiety drives stockpiling that removes notes from circulation. This is a system designing its own fragility. Every note stuffed in an emergency kit is a note that doesn't flow through a shop till, weakening the merchant and ATM ecosystem that would need to function if the emergency actually arrived. Without deliberate policy intervention — the legislation Lane referenced — the cash network could hollow out precisely when the threats driving hoarding make it most necessary.