[netsharc]

There's a blog post I read once which title was something like "How I accidentally started a bank" about a dev who added a chatbot in his work's internal chat (I don't think Slack was a thing yet back then) that tracked what each colleague owed to each other for lunch, coffee, etc. The bot expanded to track monetary value, and in the end he realized he made a bank, where each colleague had their balance, and transactions can be made.

In theory a group of people (expandable to a society, depending on trust) could just use such an app (or even just a WhatsApp chat) to do their business transactions, e.g. in China people probably just keep a balance in their WeChat accounts, and the money just moves between WeChat accounts.