He could actually be true, once cryptos are widespread and cash is abolished, goverments will be able to monitor all transactions, how much you make, what you buy, where you work, where you travel, how much taxes you have to pay, no more privacy at all, everything will be in the hands of few bankers and oligarchs.
http://www.zerohedge.com/news/2017-10-21/crypto-currency-calm-stormI think this is possible that they could trace our bitcoin transaction once they imposed a law that will make it a mandatory for all the people to comply. If they could apply tax to our fiat currency income they could do that to our digital currency thru local exchange in which every time we do transaction to them we will required us for a government issue ID for our records and legality of our transactions by this i think they can now trace us because how we could change our bitcoin to fiat if we will not go to local exchange?