Okay, great. So why do they need to sell us tokens again? What do the tokens actually do? This is not a cryptocurrency. Why are we giving it monetary value as if it were?
1) Maker and Takers will pay fee in ZRX to Relayers (exchanges on 0x) for using its off-chain order book. Looks like first Relayer will be that guys
https://radarrelay.com/And very likely Ethfinex will use 0x protocol, as they mentioned in whitepapper.
2) Decentralized governance over 0x protocol update mechanism
You should also read this
https://medium.com/@RadarRelay/on-radar-and-relayers-30423f506587