I don’t know much about crypto currency either, but it is my guess that you have hit on the main reason it has value...people decide to believe that it has value. At the root of it though, it wouldn’t surprise me too much if these crypto currencies are really some kind of Bernie Madoff house of cards propped up by an ongoing source of new speculators who want in on the action, which maintains or increases the value.
You are correct. You know nothing about crypto currencies or bitcoin.