That could change in a second if another agency like the SEC decides it's something else. There is nothing to say that two agencies couldn't hold conflicting positions over what BTC is or isn't.

Someone holds an opinion that this is the case, it has not been resolved as a matter of law yet. It could be, in my opinion, a commodity.

EPA v. West Virginia

"The agency instead must point to 'clear congressional authorization' for the power it claims."