ICOs is just geting old, and IEOs are born to replace them,
Just like before, investing in ICOs pay back alot but very risky too.
IEOs in the other hand, is a safer way (with the big exchages, atleast), the way that investors spread their money quicker but not worry about scaming,
But with Bittrex scenario, not always right though
IEO is born to help exchanges raising their funds more easily. I saw so many projects that started last year, failed with their ICOs, then recent months they came back with IEOs. Personally, I will stay away from those projects and their IEOs due to their last failures with ICOs.