Yes, crypto-currencies easily solve that part of the problem. But, you left out everything below it. Like:

• A person have a smart phone
• A person keeping said smartphone
• A person being able to maintain an identity
• A person having the ability to remember that its a new day, they have more money.
• A person understanding the meaning of money
• A person spending the money on blow and not food.
• A person knowing what to do if their normal routine breaks down
• And a person being robbed every day

(If every vendor accepts bit-payment. Then all you need to do is have a front that sells something, then your goons, take your machine and go shake down some undefended oldies for their daily bit-transfer)