Yes, I am yet to come across a crypto (or fiat currency) that hasn't got some issues with it. Single point of failure is definitely a risk, but I'd suggest anyone who is playing in the crypto space who isn't comfortable with some level of risk should not be in it.

I'm not suggesting these cryptos for long term holdings, just a means to an end for a particular scenario for a particular short term purpose. If used right then they can do a job.