For me as my opinion, it is so expensive because there will be an increasing number of members, it is acceptable in some banks. Although we already knew that it is world wide currencies that's the another reason why bitcoin is so expensive. Basically bitcoin give a lot opportunity in order to live and stay alive in this world. it is quick currencies.
Only the community bring this into very expensive, as it become highly in demand in the market-the more it will soared high. Of course, we are happy because a big chances of earning more profit as compared in the past days. And today's price, might attract more investors to take a part of this very fast growing investment.
In my opinion if why bitcoin so expensive i think because of high demand of people and continuously increase in number who using it. Also its the low supply of bitcoin is the another reason why bitcoin is expensive.