Different uses. A juicer leaves all the fibre out of the finished drink. These will at least attempt to mulch it up into something drinkable. I would recomend having a read on juicing vs blending on google. For me personally using it for myself and a diabetic nephew I don't like the fact juicers take out all the fibre but leave the sugar. The fibre slows down the absorption of the sugars so I much prefer blending.

At 200W I don't imagine this doing anything much with seeds, fibrous greens or oats in a smoothie. You can get 300W units for less than £20 and even then the finished smoothie is worlds away from what you get with the higher end 900W+ units.