Of course it's a threat. Anything that the central bankers can't control and that can be used to transfer or store monetary value is a threat to the financial system that's been in place for decades.
Some revealing quotes:
Private digital currency is not endorsed by national credit therefore not a real currency
private digital money supply is relatively fixed, which is difficult to adapt to the needs of modern economic development
Of course they would rather like to inflate it to the moon, as they do with fiat.