Although both are valuable assets, there are significant differences between them. Gold has been regarded as a precious resource by humans since ancient times but with the change of eras there has been a great change in the needs and preferences of humans. Nowadays people give more priority to bitcoin than gold. Because they can't give maximum security even if they want in case of gold. Due to physical existence of gold, it is not portable. On one cannot hide it. But Bitcoin is an asset that is not a problem when kept in a wallet. If there is good security then there is good advantage using Bitcoin.
From these two things, of course everyone has realized that Bitcoin and gold, both assets, can be used as investments for their future and as you said, it is very likely that gold has already been used by someone as an asset that they invest in and now we all have know Bitcoin well and some people have made this asset an investment for their future like previous people invested in gold.
I agree with you that to be able to store Bitcoin assets we only need to have a wallet and must maintain the passkey properly so that we can still access these assets and it is very different from gold of course we have to really look after it because gold is an asset that has a quantity based on its price and this will makes it difficult for us to maintain it.