Platinum is valuable because it's an unbelievably good reaction catalyst and is unbelievably rare. Look at Palladium (also used in catalytic applications, and still quite rare) price charts for confirmation.

Bismuth's attractiveness is subjective, but what is not subjective is that it's found in ore in mineral form, not in pure form like gold. It's also brittle, and not easily worked to jewelry by primitive methods like gold.

Anyway, agree that gold is largely assigned it's value based on social reasons. Also would say that, in spite of its many faults, it's a much, much better investment than cryptocurrencies.