Assuming that a particular law has to be enforceable to have any meaning, would it be possible to enforce anything in case bitcoins considered "property"? If not, shouldn't bitcoins be considered "not property" on that basis alone?
Of course it would be possible to enforce a judgment. Judgment liens and jail time make the court system quite coercive.
That's why technical details matters. For example, in a lot of cases you won't be able to prove that a person received any bitcoins, and it would be funny to try to coerce the person to give up bitcoins when you don't know if he has it.
In a lot of cases you aren't able to prove a person has received cash either. Doesn't change much.