ICOs were huge in the few years back and this is the initial stages for the project to get funds from investors and VCs as well but right now it evolved already  and some projects implemented IDO, IEO and much more. IDO and IEO are far more safe which IEO it can be ensured that exchange platform held the highest trust to conduct the project's token sale to everyone wanted to participate. On the other IDO more likely for DEXes which also gives a high rate of success and trust rating as well.