Imagine you had a daily income of 40$ each day in bitcoin, what would do with them and where would you invest them ?
It is still much better for you invest it to buy a coins whether in trading platform or potential ico that has promising project. Then do some trade in the exchange site, besides 40$ is enough as daily profit.
I think it is possible to get good gains in trading with this investment. However, it is important to be aware that certain price variations are very difficult to predict. In certain situations Bitcoin is very bullish, but unexpectedly there is some price fall, and in certain situations the investor only understands the causes of it hours after the event. I think it is important to be aware of these risks, and I also think it's advisable to invest only part of that money, because of this instability.