Call me paranoid but I think governments of the 21st century ultimately want the ability to track every single transaction they can.
However, I think it's actually the current unregulated crypto currencies ecosystem that should worry people far more. Consider the shady people that operate this space and their ability to mine all kinds of data. People might be surprised how valuable and useful behavioral data of individuals can be, especially when it relates to how they behave when dealing with speculative and uncertain dynamics (like e.g. the realities of crypto currencies themselves). That's all I will say about it.
And they're almost inevitably corrupt.
see Common Reporting Standard: https://en.wikipedia.org/wiki/Common_Reporting_Standard