The difference between Bitcoin and gold isn't in how either stores value. It's in maintenance costs.
For gold to retain value, you need to maintain human civilization, so that gold can be used in trade. For Bitcoin, you have to maintain it too, plus you need to keep paying an unbounded, ever-increasing, absurdly high price in energy use. This is IMO why cryptocurrencies are a serious problem, and also why they're unsustainable in the long run.
You're only talking about proof-of-work cryptocurrencies, and bitcoin especially. You should research more on currencies that use a less power intensive PoW algorithm, or a different algorithm altogether that might not use anything more than the energy of one computer.
For gold to retain value, you need to maintain human civilization, so that gold can be used in trade. For Bitcoin, you have to maintain it too, plus you need to keep paying an unbounded, ever-increasing, absurdly high price in energy use. This is IMO why cryptocurrencies are a serious problem, and also why they're unsustainable in the long run.