It seems you don't actually know the meaning of the word "using". When one passes bitcoin from his address to another person's address, he is not using Bitcoin, but instead, he is transferring Bitcoin. Gold is for example "used" - by millions of women and men everyday to adorn their bodies. Cell phones are "used" - for calls or texting. Dollars are "used" - for settling loan debt. You don't need to sell gold, Dollars or cell phone to a greater fool to make money because these items are used for their inherent qualities, rather than for speculation only. Bitcoin on the other hand cannot be used by anybody anywhere since it is just a number associated with an address. That's why you can only transfer it to a greater fool for speculative purposes.