I use it for trading because I find the price of the ETH very reasonable. But sometimes I use it for all of the above. Its a great crypto currency and I see a good feature for it.
ethereum does have many uses besides we trade ethereum we can use it for transfer fees and in my opinion that is why ethereum is one of the coins that are in great demand because ethereum depends not only on its price but also its usefulness which makes its potential in the future very good