You can't consider the problem subjectively. Whether the value of Bitcoin is useful to you is your own opinion. Some people think it is very valuable. There is no reason to deny. If you think there is no value, no one will force you, but the price is now on the market. The step-by-step growth is because more and more people believe that Bitcoin is valuable. If the number of people decreases, the price will also decrease. Therefore, the value depends on the person.