It seems to me that bitcoin is going to continue to eat gold's lunch, just as it has done in the past 10 years or more, so on an individual level you likely need to figure out how much to waste your time, energy and value to place it into gold... but whatever, each of us need to decide for ourselves the extent to which we might end up diluting our bitcoin investment into things like gold... I would suggest don't waste your time and money to invest any more than 10% of the value of your bitcoin investment into gold, but hey, you can do what you like.
Your observation is valid that Bitcoin can potentially replace Gold as a store of value gradually. However, it is important to note that Gold has been considered an important asset and hedge against fiat currencies since the dawn of human civilization. Furthermore, a significant potion of world population is unfamiliar with Bitcoin but they know the value of Gold. In this context it will take long time before Bitcoin can effectively replace Gold. Therefore it is a good suggestion to incorporate Gold in our investment portfolio to certain extent, thereby achieving diversification benefits.