It will always be the user and not the technology. The lack of knowledge and understanding is really what drives the risks in any kind of industry. Let us have an anology: for instance you would want to learn how to drive a motorbike the risk of being in an accident is not to be blamed to the bike but rather your knowledge and experience on how to drive it.
Users can expose flaws in the technology but if the flaws aren't there in the first place then there's nothing for them to expose. The biggest risk for investors is always loss of capital, aside from that I don't really see any risks.
Yes, the technical flaw is that cryptocurrency is the most deadly, but the probability of this happening is almost zero. Especially if the main coin depreciates sharply in the event of a loophole, the probability is very small. Vulnerabilities in trading platforms are usually more likely to occur.