Yes. Of course even the US dollar was backed by gold until 42 years ago. As you said, I can pay taxes with dollars. I can go to the NYC 24 hour USPS post office right now and buy commodities with a dollar. The government could privatize the Grand Canyon and compensate dollar holders thusly.

The kind of delusion thinking seen here about Bitcoins is akin to the delusional thinking I heard in 1999 regarding tech stock prices. Does anyone remember when Cisco's market cap was over half a trillion dollars? But Cisco actually did (and does) something that creates and stores real value.

There's all this talk of how Bitcoin is easier than this or that currency. Well it's (possible but) not easy to short Bitcoin. I certainly can short the dollar in a number of ways. I'm sure if Bitcoin was shortable it's price would not be where it is. It certainly means the inevitable fall will be harder though.

It's hard to say when Bitcoin's worth will crash, there's a lot of money sitting out there, waiting to speculate on something. But inevitably it will crash.