If eCash's primary use case is peer to peer transactions, I assume you mean payments as well (sending money to friends and family, but also paying for goods and services). How will people pay for goods and services? In developed countries merchants need a payment system that integrates with their inventory system so they can easily keep track of inventory and orders whenever a payment is received. This integration is facilitated by developers. In developing countries, inventory tracking is often decoupled from payments (you pay with whatever you want, then the seller updates the inventory system). XEC can potentially work here through Cashtab without additional developer support. However, there would have to be a truly catastrophic loss in value of fiat for this migration to happen because developing countries have a massive mobile money network effect (the telecom companies have monopoly of digital wallets and both on and off ramps for exchanging the digital wallet balance to cash and vice versa)