The ICO boom is gradually fading away, so IEO has replaced it. IEO provides an increased level of confidence in cryptocurrency projects, because the exchanges that host crowdsales are actively involved in the fundraising process, which increases the effectiveness of the crowdsale. Consequently, IEO can become a standard model for raising funds in the crypto space, and maybe even create the next fundraising boom. But while I'm watching the development of IEO, I'm not going to participate yet.
Actually, there is no improvement in security for IEO compared to ICO. The project can still be a scam or a fail and you'll lose the same money how you invested in an ICO. It's a wrong assumption that IEO are safer and people will notice this mistake if it's too late. They will all say 'IEO is so bad I lost all my ETH'.
An IEO doesn't guarantee that the project will be succesful. If people think and IEO is a guarantee for success that will lead to bad disappointments.
Important is a good project idea and an experienced team, not if it's an IEO or ICO.