In some cases people have taken the time to work out a set of incentives that allows a market that previously needed to be operated by a corporate entity to be operated without central control.
Such an incentive scheme has intrinsic value equivalent to the coordinating body it replaces. An ICO for such a scheme is not necessarily a scam.
Certainly the vast majority of ICOs are scams, but not all. The vast majority of beggars sob stories are lies, but not all are. Sometimes someone really is in a tough spot and needs a couple dollars.