I think people are still buying bitcoin because they know that bitcoin prices will continue to grow and will continue to increase so that if invested in bitcoin will still be profitable
People in this days still buying bitcoin because of the good benefits that they probably get in the future. Because bitcoin is very promising and trustful to earn more money in the right time investment plan. That's why they are still buying besides of it's very volatile behavior, because they always think that bitcoin will give them always good benefits and profitable future will comes into it.