If you are buying Ethereum now. The cost would be lower to exchange for Alts.
Most crowdsale have the token amount pegged to ETH. You can buy more ETH for a lower price. Therefore, you get more tokens for your Fiat.
what if the token price falls when the token is listed on the exchange? for example:
you invest 1 ETH to get 1,000 tokens and the token price drops to 500 tokens per ETH when the ICO ends and your token is listed on the exchange, of course, you will loss if you experience it and that means your idea is still at high risk