The idea isn't new to be honest & that's mainly what most exchanges coins / tokens do (KuCoin, Binance...) you name it, any exchange coins / tokens are some kind of utility one that reduces mainly FEEs & Profit Shares among their holders / traders on that exchange.
They'll be making a big mistake not listing their token into a good exchange, even a Dex one like IDex (at least) so they get the needed attention & liquidity for it o people look for it. Listing their token MAINLY & ONLY into their exchange won't make a big difference, people tend to use what's already there & proved to be trustworthy not some new launched exchange (i won't call them SCAM though, but let' face it, this is the reality).
They'll have to work really hard on marketing & make people putting their cryptos into their exchan,e that's the big ste i say. Also, i hope their exchange is Dex one not Centralized one because it will be hard to make marketing for it unless they have a good team behind that.
The exchange is not Dex. It's fully legal (registered officially not in an offshore county) and will have KYC