Cex.io is still generating around a 100% annual return, plus the fact that you can sell it to get your original investment back, so the fact that it is a few cents a day is not the point. The point is you could invest a lot more and make 100%. The problem is that there is risk. But, yes, if you have only a small amount of money to invest, then the few cents a day return is a problem.
That is a classic case of new person not looking at the trendline and only looking at the current rate of return. It s the reason why people have lost thousands of BTC to cex.io and why ghash.io has it's own farm.
I will gladly bet 1 BTC including escrow with anybody who thinks they get 100% ROI annualized return from cex.io without actively trading.
Look at the price per GH/s over the last 8 months
I've been with them for a week. GHs go for .0037X lately. I can't imagine making back my ROI through mining alone, definitely need to be active to sell GHs when they start to drop and buy when low. (which I did today when people dumped a bunch, doubled my initial purchase lol)