As you know IEO trend is growing but i feel IEO is profitable only for those who invested in token sale but who have purchased altcoin after launched they suffer loss majority of the investors ,as the BTT and some other altcoin examples of IEO.
Both IEO and ICO not profitable today, IEO always have lower price after listing and ICO always delays for listing their coin after ICO sold out, now only trading altcoin or bitcoin and holding both them to get profit, left for investing with IEO and ICO because always dump price after both investment kind listing with exchange market, maybe have other investment kind at the future.
For this reason I stopped investing in ICO/IEO. Now I prefer to trade altcoin that was just listed on the exchange, because the hype is bigger so it's faster to get profit. e.g. like TCO, when it was first listed on Digifinex the lowest price is 27 sat, because have a big hype, a week later the price is rise up to 2600 sat. Just imagine how much profit you can get in just 1 week? Although there is no guarantee of profit, but at least my time is not wasted just for waiting until ICO/IEO ends and their tokens are listed on the exchange.