Value as a collector's item (the same principle as the activities of people who are collecting rare metals, stones, shells, stamps, paintings and baseball cards). Value, which is based on the fact that other people will consider your collectibles valuable and will want to buy it, thus enriching the previous owner. Gold is valuable for these very reasons. Not because it's shiny (many things too shiny), but because it is rare, durable, mobile and available for collecting. And in the hands of the owner, it can only increase your value directly proportional to the number of people willing to get it. Bitcoins are valuable as collectibles. Their reliability as "guardians of values" depends on the number of people that use them. The more people believe in the seriousness of Bitcoin, the higher the confidence in the payment system.