https://www.deepdotweb.com/2016/01/23/bitcoin-playing-an-increased-role-in-crime-europol-says/Would you believe that the existence of bitcoin has increased the number of criminality in some countries in the world. This is the issue that was being thrown by the EuroPol and the UK Metropolitan Police. According to them bitcoin has played a huge role on the increasing criminality in their area. They added that a huge number of cybercriminals were using bitcoins in their activities.
This just shows that as bitcoin develops both advantages and disadvantages will tag along.
Actually, this is in a way, understandable. Nothing unbelievable, criminals obviously don't wanna get caught, and bitcoin is the decentralized currency for all of their needs, it is anonymous, secure, and the government can't tap in or track transactions, it is totally upto the person to decide what he uses it for. And this was definitely upheld in practicality by Silkroad and other such websites that have been taken down since, but new site of this kind are emerging everyday.