Yeah it is an opportunity if you get to buy ICO coins . But we should be very careful on the selection of coins. We should make a research of the particular coin we are going to buy. Volume of the coin and its market cap are to be observed since that help us to predict whether the coin is worthy or not.
If the coin is good, do buy it because we can gain more profit of it at the end. Because sooner or later everyone will start buying it at the higher price while we would have bought it at discounted rate.
I agree with your points, but I won't say it is per se "the best". There are so many different ways and means to invest in the cryptocurrency market. However, if there is on thing that is somewhat sure, ICO is the easiest way to invest or at least get a hold of tokens and coins. It doesn't take too long, even at its longest, it wouldn't take years and years to be realized. Thus, you won't have to fear that your investment might rot or lead to nothing. Also, in ICOs whether it prospers or not, you have a safeguard to have your investment returned, either as is or with a profit. Either way, you don't lose much.