Following the footsteps of Binance many other crypto exchanges have open opens doors for IEO following is my opinion based on my experience.

1)Not Everyone can participate

You heard it right, you can't participate if you get late like 10 seconds because most of the IEO have sold within few seconds , so you have very small window of time to grab on some.

2)Aftermath of IEO is worst

well when the tokens are distributed and exchange starts trading you will see massive fall in a price because of people try to sell in profit , people who didn't able to participate in IEO try to get some but take a loss because of sharp fall in price that's the most worst part.