I think yes, ieo is more profitable than casual ICO, because ieo provides a good listing on good exchange and it helps to make coin more liquid.
That is one of the advantages of the IEO compared to ICO. But in reality investing people want to make a profit. So if investing in the IEO is not profitable, of course people will invest in the ICO. Because what I know is all investments, both IEO and ICO investments do not guarantee a profit. And now many people prefer to invest in the IEO.