"The bitcoin is backed by math argument" is kinda silly if you ask me. It´s backed by people who belive in it, but it have no other use than a medium of exchange, therefor it will fail.. In the long run, or short run. It could even be tommorow who knows. The problem is that the source code of bitcoin can be copied to infinity and create infinite new eCoins, you cant do that with physical things like gold.
You can also do something else with physical things like gold rather than use it as a medium of exchange, you cant do that with bitcoin.