Maybe yes and maybe no. It can be a substitute for people who are familiar with bitcoin and explore the pros and cons of bitcoin investment because we know for bitcoin investment we need supporting equipment, especially internet access. But for people who are not familiar with bitcoin, they will prefer investing in gold because they don't need equipment and internet access, especially, just by going to the local market so we can buy and sell gold.
Therefore, in my opinion, bitcoin replacing gold maybe can or may not happen.