I do something cool for a famous person, and they give me a coin. Now that coin becomes something like a trading card, which I can collect and trade
The article's description of the system is too vague to pin it down, but I think you've got the right idea.
Famous people can give someone who they want to reward a personal token like their signature, that can be given to others (as a gift or for money). This can be like a digital version where people can display online their collection of famous badges, each cryptographically verifiable by person, date generated (so you can boast of "before they were famous" badges and "on the day of her achievement" badges), and also level (bronze, silver, gold).
But I'm not sure this is any better than money for more physical rewards, like a lunch date with a famous person.