There is nothing backing gold either except a series of quantum fields and physical laws that confine energy into a particular pattern. Bitcoin is backed by a series of mathematical algorithms and Boolean laws. These limit its creation in exactly the same way gold is limited by physical processes.

True, there may be a few industrial uses of gold, but nobody tries to argue that is what gives gold its value. If the math behind Bitcoin ever fails, it will become worthless. If Star Trek style matter replicators are ever invented, gold will become worthless.

It is naive to say gold is real and Bitcoin isn't. It's just personal bias that makes you think that. At our current technology level, both can be considered to have backing. You're welcome to your biases obviously, but they aren't universally accepted and based in fact.