If there is no central regulator, then the price of the currency makes a mad sprint up and down, which we clearly see in the example of bitcoin. Therefore, investing in such a coin is very risky and dangerous. But on the other hand, whoever doesn't take risks, will not earn a lot of money.
Exactly, that is the danger in bitcoin. There is money involved and we trade and transact with people who we really do not know exactly. And that is the point why it is called as trading. And that is the risk. Well, besides since bitcoin is a cryptocurrency, there are safety measures in our wallet that we may hold on too. Risk is part tho.