For RP, immersion and character development. Or just for fun and giggles.
As far, as we know (from backstory) Ark colonist are only humans. We see only human colonist (male/female) model so far. So probably no, but devs say something about alien races in future iterations of DU - although not playable ones.
But hey, you can always "role play" cyborg/robot, using "human" in-game model. See David from Prometheus for example or EDI from Mass Effect.