I also think he means DEX. In a few months or years there will be better ones where you can trade coins not only ethereum tokens.
You are right, IDEX exchange every day becomes more popular, but in order for their servers to withstand the load they need to think how to stop soft-bots from trading.
Speaking of Dex:es, some of them are unregistered and under the eye of the sec now. I am guessing lot's of smaller unregistered exchanges will quit soon.