The UI is not ready yet, that's the main reason I guess.
But we will get there, it just a matter of time and having the resources to do it.
The most important thing is that we have now a very solid technological foundation for the GUI (web sockets + react.js), so it shouldn't take much time to make it similar to Poloniex or Yunbi.
Even if Cryptonomex doesn't do it, some other third-party company will take this opportunity having the financial incentive in the form of the referral program.
80% of the job has been done, this is the last 20% missing.