Quadriga CX is a crypto-currency exchange. The only person who knew the password died and now the exchange cannot access $140 million dollars of bitcoins. Stories abound of people forgetting a password and losing their bitcoins. But this is an exchange that has lost the password. Read more.
One problem is that bitcoins are ether—not tangible. However, I never see or touch most of the dollars in my paycheck, which is electronically deposited in my and mostly goes to the many electronic bills. The primary problem is that the exchange was badly managed.