Okay I think see where you're coming from. Correct me if I'm wrong, but you wouldn't consider Bitcoin money until its a store of value, medium of exchange, AND unit of account in a large enough market. In other words, its in the process of becoming money, but its not money yet.

On the future of Bitcoin overtaking fiat, I don't think its absolutely guaranteed. I do think that its more likely than not. Fiat is guaranteed to go down in purchasing power. Bitcoin is currently volatile in purchasing power, but I believe it has a floor due to its network effect and some small portion of the market finding its properties very useful. Eventually, fiat's purchasing power will drop below that floor. All Bitcoin needs to do is survive until then. Its not a given. The US Government could suddenly grow a conscious and brain and abolish the Fed. Bitcoin could fail due to a black swan event. But I think its more likely that Bitcoin makes it. I am literally putting my money on that happening.