I think since exchange is behind IEO people has more confidence in investing into it than ico. I have lose money in 2018, to ico projects and when this IEO come up I have to careful because it looks the same just that exchange give some lift to one.
You are right, exchange has an important role in restoring investor confidence in new projects. the greater the exchange that works together to make an IEO sale, the greater the interest of the investor. but it does not guarantee that the project can be a big success, all still need research before we join the IEO.