I almost always use bracketing. I do so for a couple of reasons. First, I want a hedge against my own exposure errors. If I am a few thousand miles from home, and will not get a chance to re-shoot the image anytime in the near future, I feel much more comfortable having three exposures to work from later than just one which might be a bit off. Yes, by shooting in RAW, I can make corrections on a shot in post-processing, but I much prefer to start editing with the best exposure I can. Memory is cheap, so bracketing the shots gives me a little less stressing at little cost. Secondly, I occasionally will decide much after the fact that an HDR treatment might improve the overall effect of the final image. By consistently bracketing, I have that option available latter if I decide it might be worth using.

I think the original question seems to play to a misconception that many of us unconsciously have about "professional" photographers. There seems to be a deep down belief that the pros walk up to a scene, scope it out for a few seconds, raise their cameras, snap off a single frame, and walk away thinking, "yep, another winner". My belief is that truly gifted photographers spend a great deal more time and effort "working a scene" than a true amateur. They will put a great deal of effort into approaching the shot from numerous positions, with many differing settings. Bracketing is just one more tool they can use to get that much closer to that perfect shot.