In a way yes. It is not going to replace the cash as we know it but overtime it could. The biggest threat is to banks. The reason I say that is currently if we want foreign currency we have to go through all the legal hoops to obtain it at an increased fee. The banks make a fortune from this currently.
In the future or even now we can take crypto currencies in our digital wallet and there is no need to worry the banks. There are bitcoin ATM's around now that we can convert coins to cash.
Governments feel threatened as they are going to miss out on taxes and can't control your crypto. more and more people are switching to this to keep it away from the tax man.