Mobile wallets aren't just for getting in and out of Starbucks that bit quicker. In several parts of the world, many people rely solely on mobile wallets for all their financial needs. These are particularly prevalent in Kenya, for example, where 58 percent of adults manage their money with mobiles. And we're not talking about smartphone apps and contactless payments here, but simpler systems like M-Pesa that work on feature phones and verify transactions via SMS messages. These are entirely reliant on the presence and performance of mobile networks, though, which a project called DigiTally is trying to address with a SIM sticker that lets users make and receive payments when there's no network connection whatsoever.