There are different factors that scare investors one thing I know is it's legality, bitcoin in other countries are sometimes met with legal boundaries that makes it illegal, second is it's volatile and unpredictable market fluctuations, bitcoin as we all know is like a bubble, it may expand or compress and investors see this as a reason for not investing in bitcoin. Third and finally is the price, bitcoin cost 7.3k USD right now and some investors are scared that they will pay a huge price only to have loss rather than profit.