It was supposed that bitcoin is perfect for illegal transactions. Though, considering how the blockchain works, it can be claimed just by people who don’t understand the blockchain technology.
First of all, all transactions are trackable. Second, they are publicly available, open for everybody using the blockchain. Third, they cannot be modified or removed. Fourth, in case of fraudulent action, the person can be blocked from the blockchain access, hence, his/her bitcoins will be not able to serve.
Ethereum moved even futher. With smart protocols, the developers do not just expect that all participants will handle fairly, but they create some guarantees of legality for all transactions. Smart contracts are computer protocols that are used to verify transactions.
Lawyers undertand that the blockchain may take away a good part of their job, all issues, connected with finances. With time, when the blockchain develops and cryptocurrency will become a part of the life, and maybe, who knows, will replace the traditional money, all financial field will not need any lawyers.