As you said there is not much difference in IEO and ICO i am completely agree with that, ICO just evolve in IEO and making this a bit easy, i also think spammer just make the word ICO very bad so it is good to evolve into IEO
There's no much difference, but when you conduct IEO in a reputable exchange it means there are legit, especially in Binance as they are really doing their best for them to run IEO with those legit only and no scam, but in ICO, you cannot determine who are scam and not because scammers are also clever enough.