The whole power of governments and banks depends on coercing citizen only one form of "authorized" money, whose properties and supply is under their control. This makes it a lot easier to control people and collect taxes from their subjects. Therefore people are not free to choose the form of money that is the best for them. A free market for money does not really exist, issuing private money can even lead to imprisonment
It is not so much about issuing private money that could lead to imprisonment as putting this money into wide circulation which is problematic. Promissory notes as well as bearer bills are also a sort of money which are allowed by most governments, but their circulation is limited mainly due to the lack of appropriate payment system which would allow to use them as a full-fledged currency. On the contrary, Bitcoin is money itself, and at the same time it is also a payment system in its own right. The latter is what makes it really unique and distinguished from other forms of privately issued money...
In this way, it can be said that Bitcoin hits two birds with just one stone
