In her Sept. 19 op-ed, “Crypto has hope — and a long way to go,” Megan McArdle shed an ambiguous light on the future of cryptocurrency, highlighting possibilities and breakthroughs, such as ethereum’s new energy-efficient mining method, while acknowledging the challenges that it faces. Though I agree with Ms. McArdle’s opinion that cryptocurrencies have much larger problems than the environmental concerns, Ms. McArdle failed to stress the biggest obstacle of cryptocurrency: adoption by national governments for the faster, easier and safer transactions it promises.