In my opinion Bitcoin is not a money. As a digital good, it is traded/bartered as a medium of exchange for other goods / services / cash(national currencies). In itself it is not money / currency - as it is not a store of value backed by any issuer of authority.
What is money if not a "good, traded/bartered as a medium of exchange for other goods"? Bitcoin is true money precisely because it is used in this way. And it is indeed a store of value so long as it retains a market price. Similarly, gold is a store of value to the extent that its market price against other goods is maintained. Similarly again, fiat dollars are a store of value only to the extent that their market price in terms of goods is maintained.
The fact that Bitcoin is not "backed by any issuer of authority" doesn't mean it's not a money. Again, gold is not backed by authorities, either, and it is the longest running money in human history. Both gold and Bitcoins are money because the marketplace has chosen them as such. Fiat dollars are money because the government has chosen them as such.
I trust the market more than the government to decide what is real money.