Dave Jevans, CEO of the blockchain security company CipherTrace was qualified by a Canadian court as an expert on Bitcoin. These experts can help testify or support a legal team to help attorneys understand how crypto works. I think this is great to help catch those who are moving mass amounts of money, narcotics or anything else that would put other people in danger.
What is wrong in moving mass amounts of money unless there is an illegal intent, this is nothing exceptional, if there is a technology that the court needs assistance they usually turns to these experts to prove the case and explain to the judge so that he could understand the evidence provided. We had some high profile cases in the past and i am sure there were experts helping them with the case during the prosecution.