posted this yesterday in a comment and I want to re post it. Bitcoin private keys are coordinates to buried treasure (aka Bitcoin).
Bitcoin private keys are not titles or deeds.
There is no ownership in Bitcoin.
The number 7 is a valid private key on the bitcoin network.
People have spent BTC from the addresses associated with the private key you can generate with the number 7.
You cannot own exclusive rights to the number 7.
Current ownership title and deed laws cannot apply to Bitcoin because you cannot own Bitcoin because "Bitcoin" is just a set of signatures and UTXOs associated with a number (private key).
And you cannot own a number.
All you can do is safe keep coordinates (private keys) that have treasure (Bitcoin) located at them.
You cannot "Own" Bitcoin.
It will be interesting to watch legislators try to prove that you can own Bitcoin (Bitcoin = a set of signatures and UTXOs associated with a number).