It can be profitable, and in a few occasions developers deliver the product. But it doesn't mean it is a good way to invest. I would prefer traditional investments, where developers are not paid before the product is delivered, and regulation prevents them from running away with the money.
Yes, 99% of ICOs are cash grabs and scams in the long term but it doesn't mean one should not invest in ICOs because the hype around the ICOs are huge when they hit exchanges it will be more than 2x atleast. This is an easy way to increase your ethereum without much risk.
I would also say that it is better to participate in the signature of the company and work for a quality and perspective project point A, even then you can trade a token and not spend your etherium.