I can understand why you think that IEOs are safer than ICOs (for reputable exchanges only), since to be listed on Binance for example you have to pass some sort of verification test.
But from an investment standpoint, I think that's where it ends. The only advantage is that you have somebody else that did the work for you already (some due diligence), which you should do for any investment - no matter if it's an IEO or ICO - anyway (make sure that the team is legit etc.).
Another advantage might be the hype that they are experiencing currently - which leads to the big pump&dumps that have already been mentioned in previous posts. But that is nothing I would think of as positive actually.