Any dental work, including porcelain veneers ought to be extremely smooth when it is completely finished. There are two main places where you may notice the smoothness (or possible roughness) of veneers. The side you will be most aware of is the Inside portion where your tongue will touch the back of your teeth along with the inside edge of the veneers. The junction where the veneer meets your tooth is an area that ought to be highly polished. There is no reason why this shouldn't be virtually invisible to your tongue. A great cosmetic dentist will not only make sure that your smile looks great, but also make sure that it all feels smooth and natural. The other side where you may notice the surface is the front side that your lip will be gliding over. Most of the time this side is not touched by the cosmetic dentist during the fitting. In general the ceramic lab will glaze this surface to an extremely smooth polish. Great cosmetic dentistry ought to leave you with a result that looks the way you love, and also feels very natural.
Yes, veneers are smooth. Truly cosmetic veneers, whether porcelain or direct bonded, should mimic the natural anatomy of the teeth they are covering. Depending on how "natural" YOU want them to be, determines how much anatomy the dentist and/or lab technician adds to the surface.