With a blender, you can make things fresh and from scratch. It will make it easier to eat raw food in your diet, especially greens. It produces a nutritious breakfast on the run. Many cool desserts and soups rely on the trusty stick blender or vitamix.
However, amylase is present in saliva and begins to digest your food as you chew it. Chewing is also linked to the pleasure and satiation centres in your brain. Blending will allow you to eat far greater amounts than usual of fibrous foods, which your stomach may not be prepared to digest. You will also tend to eat quicker. Fibrous foods tend to have a lot of sugar, if the stomach is unable to digest all of the sugar before they move to the intestines, they can ferment, causing gas and irritation to the intestinal lining. No sugar is meant to be in the intestine, it is full of bacteria, which can grow out of balance if constantly being fed excess sugar.
The long and the short: chew your food. Even if it is blended.