What's the commodity behind bitcoin or is it a fiat? metals? hard drive space? What is the inherent value that bitcoin represents?
It's fiat, but it's not government fiat.
In theory, it's un-forgeable. Time will obviously test that, but the money supply is out of the hands of government with BitCoin.
The "value" is that, among those who accept it as currency, the electronic representation of 1 BTC is something that cannot be taken from another person by any mechanism other than the consent of the owner.
Frankly I think the best use of BTC is to move wealth across political and geographic boundaries without accountability to governments in between those locations.