Many ICOs have their token sold at a fixed price vs. the ETH. For example: 1 ETH = 1000 Tokens.
So does it really matter if the prices of ETH/BTC is dropping?
If anything, then buying now you get more Tokens for the $, right?
It is best to buy ICO tokens at the beginning of the bull market. If there is a real turn of the market now, I'm sure that such investments will bring a huge profit. Of course, everyone decides for himself, but I think that now is a good chance to buy cheap.