Like what general investors in BTC have decided, its not meant to be used to buy groceries. Its a store of value
Well, bitcoin is very profitable and it is a good investments. In addition to that, as of now many people already invest in bitcoin because they know that they could earn a lot of income and it has a high value in all cryptocurrency. Having bitcoin is an opportunity to become rich in the future. Lastly, many people believe in bitcoin that it will help them to get rich in the future.