Cyber Attackers Crash Muni Computer System Across SF

The entire message read, “You Hacked, ALL Data Encrypted. Contact For Key(cryptom27@yandex.com)ID:681 ,Enter.”<p><a href="http:&#x2F;&#x2F;www.sfexaminer.com&#x2F;hacked-appears-muni-stations-fare-payment-system-crashes&#x2F;" rel="nofollow">http:&#x2F;&#x2F;www.sfexaminer.com&#x2F;hacked-appears-muni-stations-fare-...</a>

Using an email account seems suboptimal. Why not do it over Bitcoin or other digital currency?