The ultimate aim of projects who raise funds via ICO and IEO methods are to raise money to fund their projects and I think projects actually prefers ICOs to IEOs because there would be no middle-man (exchanges) to share the funds with or to give large amounts of their tokens to,
middle-man is needed to reduce scam fund raising. on the other hand, it costs more. but I think it is no problem at all
additionally during the days of ICOs, projects could raise much more funds via the ICO tokensale method, we used to see hardcaps of $10m and above but with IEOs, their hardcap is much smaller although it's almost guaranteed that they would hit it I'm a short period of time, mostly within seconds of opening the sale.
that's good for IEO, we can know that IEO aims to NOT get funding as much as possible.
IEO has clear calculation how much money needed, and set with it.