1) a currency must be exchanged easily. Now it's impossible to pay a coffee with BTC (scalability, fees), but we can pay a car because in the second case it's not necessary to have timeliness (it happens, for example, with wire transfers).
2) a currency must be a unit of account. How rich are you? You can answer me by quantifying your wealth in FIAT. But BTC is volatile. Today you can be rich and poor tomorrow. Currencies are stable (in most cases).
I think that BTC is currently an asset, the "gold of the future". I don't like this concept, but it's true.
Community must do something to reverse this transformation.
Only in this way Bitcoin will be able to fully express the potential of blockchain technology.
What do you think about it?
Let me give you a legalese view on this. "Currency" is a legal tender of a specific government which is widely used and accepted as a form of payment to all countries worldwide. While "commodity" is something of value that has monetary equivalent, which may, in some instances, be used as a form of payment. You see, both have intrinsic and extrinsic value but it is the acceptance of it that sets them apart.
These so-called cryptocurrencies are sui generis because they were built into the likes of a currency but has the features of a commodity. Hence, as for me, they are neither currency nor commodity. They are a kind of its own which, up to now, cannot be classified accordingly because of the absence of a concrete law or regulation specially designed for it.
The thing is, though, there are governments and merchandises that already accept Bitcoin as a form of payment. So here, we can see a slow evolution of how Bitcoin will be classified later on. Again, it is the acceptability that is controlling in this aspect. Of course, acceptability should come black and white in the form of a government regulation.