Crytocurrencies, after a wild ride, may be at a tipping point.

Bitcoin and other digital currencies exploded in 2017 only to spend much of 2018 losing a large chunk of those gains. A unit of bitcoin, the most popular cryptocurrency, climbed from under US$900 at the end of 2016 to a high of almost $20,000 in December 2017 and has since plunged to a...