Sure. But the carrier of value is irrelevant. It's weather or not you control it on your own behalf(IOW-owns it) that matters.
you are getting there .... one can control the private key, but not absolutely the blockchain ... so is there really any ownership? (unless the State decides to give the blockchain legal standing.)
I cannot see why not. With the bank they control the files, with BTC the account-files are open. Only difference is that in the bank you show an ID or use your card, while in the blockchain they are protected by your passphrase and the native encryption.
That Bitcoin is not specifically described in the law, does not mean that it has no legal standing. It's still a valuable asset. It just means that it is yet to be clearly defined. This can happen in two ways - either it is defined up-front because it's become large/important enough, or it is defined in a court case (either initiated by the body that issues tax or by some taxpayer that want clarification).
This is being discussed in the EU atm, and probably other places aswell. Don't think it will bee too long before it has been cleared up what kind of asset the BTC is counted as. (Then that may be challenged in court offc.)