Limited Concurrent Transactions

 The Bitcoin block system requires connection and confirmation from the peer-to-peer network to be verified. Because each block contains a limited record of transactions and an upper limit to the number of new transactions that can be written, there’s a limit to how many people can buy and sell with the system at any given time. As more and more vendors and individuals use Bitcoin to do business, the number of transactions per second increases, and the peer-to-peer network is becoming congested, with some operations without transaction fees taking hours to clear. Whereas conventional payment systems like credit cards can simply expand their connections and processing power to speed up processing, the isolated peer-to-peer nature of bitcoin doesn’t allow it to scale with the global financial system.

Black Market Appeal

A central principle to the design of the Bitcoin system is that there is no single transactional processing authority. As a result, no single user can be locked out of the system. Combine this with the inherent anonymity of transactions, and you have an ideal medium of exchange for nefarious purposes.

Bitcoin has become an ideal means for commerce in illicit goods and services. The quintessential case is the Silk Road, a dark web site that allowed users to anonymously trade items like drugs and fake identification, all bought with Bitcoin thanks to its untraceable nature. The story of Silk Road’s illegal trade didn’t even stop after the US Drug Enforcement Agency and Department of Justice shut down the site and seized its digital holdings in 2013. A Secret Service agent was charged with stealing over $800,000 of bitcoin from the investigators, who had held the seized digital currency to be auctioned off for the benefit of the law enforcement agencies.