Blending vegetables into a smoothie (without straining it through a mesh like a nut milk bag it’s not technically a juice because the fiber is included) is a good adjunct to a healthy diet. Unless you’re juicing many fruits it won’t skyrocket your blood sugar. A good rule of thumb is not to juice more fruits or vegetable than you’d eat.
Eating the produce is best for the full fiber benefits to your gut microbiome, for chewing to stimulate digestive enzymes to help break down your food and to help eat mindfully.
Blending into smoothies is a great change but it does encourage some folks to dump in ‘stuff’ to make is taste ‘better’. You will have polarized answers on whether blending or raw is better. There are advantages to cooked veggies, raw veggies, blended veggies, and powdered veggies. Personal preference and lifestyle weighs in also. So, no one can really tell you what is best for you in that regard.
For me, steamed veggies with oil or some other health focused flavoring is my preference, and suggestion. I also include powdered veggies in my shakes to ensure I get enough on busy days during which I would not eat veggies if they were not powdered.