When you hold a title like Doctor, Reverend, Rabbi, Imam, Sergeant, General, Mayor or President that means something. You have earned the title or have been chosen or elected to be elevated to lead and serve. To me its a matter of respect to address someone by their title. It’s important that people in such positions know they have a responsibility with the title given to them. Professional abbreviations matter too because people have worked to become an expert in their chosen field. All this comes down to showing that people have reverence and respect for others and to recognize their achievements.