Better is a relative concept. Fat in Greek yogurt comes from milk and while the fat in milk is saturated, it is a necessary part of our daily diet. The key is moderation. Fat can help with satiety and also provide a creamy texture to our Blast that some people enjoy. The amount of fat for a 2% Greek yogurt is around 3g (15% daily intake) in a 7oz serving. What you may find more helpful while not losing any creaminess is use 1/2 the amount as suggested and use a non-fat dairy source as the other half like non-fat yogurt, almond milk, or other nut milks.
Perhaps I was incorrectly thinking the fat in yogurt was a healthy fat, so if that is incorrect, I would prefer to use the no fat yogurt. It's in the smoothie anyway.