There was a period when people erroneously thought that bitcoin was anonymous and secure.
If the NSA was not working to track down the premiere currency of the dark web and of the nation state actors they work counterintelligence against, this would be dereliction of their duty.
This is like suggesting the FBI tracks down "USD" users. No duh, law enforcement and counterintelligence requires regulation of the financial systems in use. Any unregulated financial system is a hive of villainy and scum as a truism.