So far I can't think of a cryptocurrency that went to 0. But you are right there is some risk in anything but what do you suggest I change the title to if it's not completely risk free but it's the lowest risk available that I know of? Bitfinex doesn't even compare because that was a centralized exchange which never had low risk assumption.

As far as risk, compared to everything else the Steem Dollars are low risk, I mean what else is there to compare it to which is lower risk? But risk free, even government bonds could be said to have some risk but chances are the government wont collapse and chances are Steemit wont collapse. Bitshares, even Litecoin, haven't collapsed, and Dash is going strong.

But yes, there is a risk that all governments in the world could ban Steemit simultaneously and kidnap the developers to shut it down. But this isn't centralized like a bank or traditional startup, and witnesses can be anywhere around the world.