Im not sure i understand. Do you mean to say that they are an efficient currency/banking system in one? Im not sure why that means they have value? (im really no expert, and im asking sincerely)
I'm also no expert. I don't have a tech or finance background, so my understanding of these things is lower-level layman's at best. As I understand it, there are thousands of "crypto" projects out there. There are many different goals and uses for the different projects. There are some whose goals are to address inefficiencies within the current banking system, while working with currently existing currencies. There are others who aim to decentralize the banking system altogether, creating new stores of value and systems for transacting. There are some with goals somewhere in between, or altogether different. There is no "one-size-fits-all" description for all "crypto" projects, other than a common technological theory which these projects utilize. If a specific project finds success, in that their objective is reached and is adopted into mainstream usage, and there are finite tokens or keys needed by the general public to utilize the system, those now have value. How many current projects have actual case use and how many are still purely speculative... I don't know.