The benefit of bonding over Veneer is that you can conserve your tooth structure. To achieve ideal results with Veneer, the enamel, the strongest, most cavity resistant part of the tooth are prepped (i.e. drilled away) and enamel unlike dentin has 0 regenerative power. (FYI, unlike bone which has constant osteoblastic and osteoclastic activity in our body, once teeth are formed it cannot regenerate itself. That’s why dentists drill and fill and doctors put you on a cast to stabilize and let bone to heal. I heard a friend saying “I am taking Calcium to strengthen my teeth.” Unfortunately, it will do nothing to your teeth, but help the bone grow.
The disadvantage of bonding is that it is greatly dependent on the skill of a dentist and time consuming (in the perspective of the dentist: chair time will be longer but bonding is done in a single visit. Although, I prefer to make minor adjustments and fine polishing on next visit)