I just transferred NZD out of my bank account. These are automatically transferred to NZDT, which has a market for a small number of different coins. Alternatively, I have to buy Bitcoin, Litecoin or Doge - which have a larger number of alternative coins offered. So, yes, if you were depositing Ethereum, you would have to trade it into Bitcoin, Litecoin or Doge first if you wanted to buy something else. To buy using Ethereum, another option would be to use Etherdelta.
