From what I know it is a way to a make a coin more popular. Nothing is risk-free, especially in the high volatility cryptoworld, but the risk is not mainly in the investbox itself (in my opinion) but in the coin you buy. The coin might lose more value than the investbox could provide by the percentages. So I would never buy a coin just because it can be put in the  investbox, but it is a very nice extra when you already think that the coin itself is also a good choice to invest in. I bought CCT way before the investbox option appeared. Please, correct me if I am wrong.