Underperforming in what way? If I look at the charts starting from the year 2000 till where we are standing today, then it has gone up from ~$230 to ~$1200 right now. That's not really what I consider to be underperforming, unless you were talking about something else.
Bitcoin is a far better store of value tool than Gold if you ask me. One of the main benefits is that you can hide it without anyone noticing. With Gold you either need to buy a massive save, or walk your Gold into a bank vault where you rely on a third party to take care of everything. You can transfer it instantly to anywhere in the world which isn't possible with Gold that people hold in physical form. And there are more benefits of course. That's why I certainly hope that Bitcoin will turn out to be a better overall store of value tool (for me it definitely is), but it will be difficult to convince the massive amount of stubborn people that still think Bitcoin isn't real because they can't hold it in their hands.