Aside from dogs that have actual jobs which help protect society or as support. Police dogs, detection dogs, guide dogs, etc. owning a dog as a pet also has many positive benefits:
Keeping people fit and active, therefore reducing pressure on the NHS.
Good for owners mental health.
Helping people feel connected, our elderly neighbour takes her dog for 2 short walks a day, she has said without the dog she would spend most days indoors.
Something does need to be done regarding the amount of dog attacks, we have 2 staffies, both are well trained. We keep them on a lead when in public areas, we pay to hire a secure field 2 or 3 times a week to allow them off lead. We would welcome a dog licence, I think it should include mandatory training and annual health checks. But the issue is as a responsible owner we would comply, but the owners of the dogs which attack are in general not the responsible owners so would not comply anyway. Breed specific legislation does not work and I do not believe any dog should be destroyed purely based on their breed.
If we were to destroy every XL Bully, who would euthanize them all. Many vets will refuse to put down a healthy animal, rightly so.