Miss Vegan, congratulations on beginning your journey to health,NAND welcome to the board!
Most "smoothies'" even "green smoothies," contain significant amounts of high calorie density foods: usually fruit, fruit juices, and soy or other "milk.". Plus, people who favor them tend to drink them regularly rather than as an occasional treat. So, with smoothies you take in a lot of calories, and the fiber has essentially been refined by the blending such that it doesn't get to do its good work in your digestive system.
A vegetable soup that has been blended, however,is generally going to be much lower in calorie density than a typical smoothie, simply because it is composed entirely of low calorie density foods (this assumes you aren't adding nuts, olives, avocado, soy, or other higher fat whole foods to your veggie soup).
So, i think that eating a blended (you might call it "creamy style") vegetable soup would be fine, as long as you are also eating plenty of intact veggies and starches too (so that you also get the unrefined fiber).
If you find that your weight loss is slower than you like, then you could reduce how often you eat the "creamy style" soup.