No doubt somewhere in Decentralization people use it dur illegal purpose and that is not good, they misuse the anonymity and true purpose of Decentralization. Decentralization is much of a responsibility than a luxury and if not used with proper care could be destructive. I would not say Centralization is the only solution for this but these need to be a solution to track the end user of the transaction or final beneficiary. This should not limit online transactions and ease of payments or services, higher transactions fees etc after that's the main advantage of cryptocurrencies i.e. ease to accessibility. But the big transactions where the end user cash out the cryptocurrency to fiat could be validated with proper identification and security checks. Anyone earning legal cryptocurrency should not have any problems with it and it could definitely lower the illegal transactions. Also not to forget there is lot of money laundering and tax evasion is going on with cryptocurrencies which in a way affecting the global economy in a bad way. Cryptocurrency should be a means to financial freedom and eae of transactions, it should definitely not a tool or weapon to finance terrorism and Illegal activities. 😊🙏