First, because it is more convenient. When our ingredients are frozen this acts as a natural preservative, reducing the risk of food spoiling, and allowing you to prepare Frutify smoothies whenever you want to enjoy them. Juices have a very short shelf life, and in order to guarantee their longevity, preservatives and other substances would have to be used, and this does not go with our philosophy.
Second, when fruits and vegetables are juiced, their fiber is extracted. On the contrary, when whole fruits and vegetables are mixed in a smoothie, fiber is retained, which allows you to have that feeling of fullness for longer, and helps with digestion. Juices also tend to be higher in sugar, causing unwanted spikes and drops in blood sugar.