Worse, they are used for pump-and-dump schemes. You can see ICO tokens from 1-2 years ago still being traded on exchanges and having some price action, despite clear lack of results and development progress. All they do is employ bots and shills to create some buzz on social media, and some fake news and announcements, all in order to lure noobs to buy their tokens again. So, no only ICO's scam the initial investors, they all scam everyone who trades their tokens on exchanges later.