The only thing that i see danger in cryptocurrencies is the government because if the government will not agree in using cryptocurrency then if they will ban it then our hard work will turn to nothing so i think it is better if we make using cryptocurrency legal first so we don't have to worry about because the coins are legal and the government already approve it.
If the government would be willing to accept bitcoin, it is a very bad impact on the users. The fact that the state has always had control over income citizens and businesses. Therefore it is necessary to draw conclusions about whether to demand the legalization of the government or not.