I have thought that one key advantage crypto (bitcoin, litecoin, Dash, monero etc.) has over gold is that its supply level is fixed and transparent, but can this or features make crypto more valuable than gold?
Actually, Gold is also limited, otherwise it will not become more expensive within time. Nevertheless, it is quite possible for crypto to become more valuable than gold. It is confirmed by the economic steps of China. They started using Bitcoin as a reserve currency instead of gold last year. Since that, Gold has started decreasing and Bitcoin, vice versa, increasing.