they already have an exchange set up from a previous privately held project that never launched (they saw the benefit of a decentralized exchange over building another centralized one and stopped work on it to start development of the fully decentralized NVO instead) - not sure how ready-for-prime-time it is, but if it's almost complete, why not? And at this point I think there's a philosophical aversion to paying someone to list the token...I mean, why pay someone to list it if they're already going to take fees?