1. Low Profit
Most of ICO when their token listed in Market/Exchange, that price is always under ICO price. There are 2 ways to escape. Sell with low price and small loss or Hold and wait their price pump.
Or wait for working product. Don't expect project will blow over night, it is not going to happen.
2. Wasting Time
Every ICO have time to open their token sale. They will close their token sale if hit their target. Some of token sale is take up 30,45 or 90 days. Some of ICO will not stoo their token sale if not hit target. After recieved tokens, they need to listing in exchange so, you must wait again. Better if they not lock that token long time.
Better is to lock token and unlock it after they release product. All you can get is dump after ICO because bounty hunters are selling tokens.
4. Most of ICO need KYC
Some ICO is need KYC to make their security save from buyers. But, giving your identity its dangerous and not all ICO will keep save your Identity safe.
Nowadays is popular to ask kyc but that isn't the reason.