There is a risk in everything but still I do not agree with the point that bitcoin is not that good as currency. I am using bitcoin from a longer time and from that time I am observing that bitcoin is much better than any other currency which the states are using for themselves. Instead of that which is said in the title I will say national currency is not that good as bitcoin.
of course not good because the price is unstable and very volatile.
so bitcoin is widely used as a futures investment or daily trading.
maybe a store or place that accepts payments using bitcoin immediately sells their instant bitcoin after receiving the payment, I don't know how they deal with it, but clearly they still accept payments using bitcoin even though the conditions are not stable.