Facebook Inc., a centralized corporate giant with a history of customer data use controversies, is an unlikely candidate for bringing cryptocurrencies to the masses.

Yet many digital-assets enthusiasts are now hanging their hopes on the company’s new digital coin succeeding where Bitcoin has not. Facebook said June 18 it will launch the token, called Libra, next year in partnership with finance and technology heavyweights including Visa Inc. and Uber Technologies Inc.

Facebook hopes its so-called stablecoin, which is designed to be less volatile than Bitcoin, will be used for global money transfers and commerce. The coin could instead become...