For example at this link https://www.thesun.co.uk/tech/5092224/criminals-use-bitcoin-for-dark-web-illegal-activity/amp/.
So if there is nothing correct regulations, maybe a lot of countries will be block this payment system.
And as the effects, price of BTC will be drop soon.
So let's start to discuss, what it the right regulations to avoid Bitcoin used as a payment for crime.
in fact many countries are implementing certain rules for bitcoin owners, but to prevent the occurrence of crimes such as money laundering it seems the criminals not only use bitcoin, because there are still many ways to wash their money, so for the regulation we leave it to each country they certainly have a certain way that is considered suitable, for example the European side by way of registering the owners of bitcoin, other developed countries by way of registering the movement of the money itself.