Their evidence is: "the firms we spoke with believe the unseen illicit activity is relatively small". That's it. The confident conclusion that it's overstated doesn't even allow you to infer if it's more or less than 50%; it doesn't even say which statistic they actually used.
If it's total percentage of transactions or sum of traded bitcoins, that isn't even that important: you can amass a small fortune in just a handful of transactions, whereas trading bitcoin for investment generates many more transactions, all completely irrelevant to the influence of bitcoin on crime.
There are other quotes from experts available, such as “Bitcoin — and virtual currency in general — is widely used in the trafficking of weapons and drugs, and in ransomware and extortion cases. It is used a lot by criminals.”
- me: criminal activity not a majority of btc use and severely overstated overall, and it enables surveillance, aka intelligence gathering for LEO/IC if properly utilized.
- 30 year veteran, ex-deputy director of the CIA:
“However, based on our research and discussions with industry experts, I have confidence in two conclusions: • The broad generalizations about the use of Bitcoin in illicit finance are significantly overstated. • The blockchain ledger on which Bitcoin transac- tions are recorded is an underutilized forensic tool that can be used more widely by law enforcement and the intelligence community to identify and dis- rupt illicit activities. Put simply, blockchain analysis is a highly effective crime fighting and intelligence gathering tool.”
“ All of this together suggests a broader point—that the illicit use of cryptocurrencies in general and Bitcoin in particular, as a share of total market activity, is cer- tainly not higher than it is in the traditional banking system and is most likely less”
Quite literally does say something/anything like what I said.