First of all, just because it's difficult to prove theft doesn't mean it's not property. Also, you're getting into difficulty of proof, which is irrelevant to what the law is.
Second, how can you argue that you don't have property rights in BitCoin and then turn around and say you could recover for them in a civil action? You're contradicting yourself. You can't have damages for fraud if you never had any property rights in your swindled bitcoins in the first place.
To be clear, I'm saying that the property rights for Bitcoin don't have a clear path of precedence to support them in current law.
I'm also saying that the criminal charges only have to do with stealing the account information for anything of value for something that is not yours.
I also said that the civil case is very hard to defend. I personally said nothing about recovery. Maybe I wasn't clear in my example. The defendant is the fraudster.
Difficulty of proof may not apply to what the law "is", but surely determines how you would represent a client.