You have clearly mentioned the major reasons why Bitcoin cannot become a legit currency and I agree with them and Bitcoin huge price changes can be a major problem for many business personals who are willing to use it with there core business to gain more profit because when a customer comes and purchase something for a one Bitcoin during that moment the deal can be very profitable for the retail store but in a few days due to Bitcoin huge price drop it can be a disaster but even we see same things happen in dollars we don't see such variations so if Bitcoin to become legit there are many qualities it should gain