Max,
Love u Man!
However, Bitcoin is really backed by what has been invested in the Network, as in the people, USD's, electricity, time, effort, ingenuity, software, hardware, and efficiency, of which cryptography is just a part.
Some people mean 'backing' to mean a central authority promises (lies) to give you something else valuable in exchange for it. Bitcoin is not backed in that sense.
But in our case Bitcoin is the valuable thing itself. I almost think some people would rather a promise to pay bitcoin instead of bitcoin itself. Afterall the promise is 'backed' by somthing. Same thing with gold. A paper dollar used to be a promise that you could get gold, gold is not a promise to get anything and that's why it's better.
But somehow without central promises gold can be exchanged for stuff and so can bitcoin.