In Manhattan, a cup of coffee will set you back about $2. Or .00098 Bitcoin. Or—here’s a new one—12,500 NewYorkCoins.

Never mind alternative currencies such as Tigercoin, Ethereum and BiblePay. There’s a cryptocurrency named for our fair city, and it’s gaining momentum.

Last week, I met two of the coin’s volunteer boosters at Gila’s Nosh on...