IEOs boost the trust level of investors, this alone makes a big difference.
You are right, but investors must be more careful of what he is believing. By the increasing number of IEO and its hype, there will be more scammers to take this opportunity to scam investors. Also, IEO is just ensure listing and not ensure that the project will be developed well.
What you said is right, there are still scammers who will take advantage and therefore the risk is still here.
However, if you will compare to ICO, IEO is less risky and proven that it could raise investments and can give to investors since they have the volume in trading sites like Binance.
Unfortunately, I haven't heard a coin that is successful coming from IEO, except those coins from Binance.