BBQ falls into 3 main classes: Backyard, Restaurant/Vendor/Caterer, and Competition.
Backyard BBQ can be either "amateur" in a competition, or just cooking stuff up for family & friends. In the Competition world, Backyard refers to a less equipped or less experienced participant, usually working off of an inexpensive kettle or drum smoker. Also, the Backyard comps may only require one or two meats for turn-in, as opposed to 4 meats in the Pro Team category.
A Backyard competitor can pull up in a large van or tow a small trailer.
The Pro Teams often have large motor homes along with fully equipped (catering) trailers and one or two very expensive smokers! Hardware for the Pro's is in the hundreds of thousands!
Obviously, commercial BBQ would also entail a kitchen/trailer, smokers, and other support. The goal is to turn out as much quantity of BBQ as possible with the least amount of prep & handling. Meats will not be as perfectly trimmed, nor meticulously seasoned as they might be for competition judging. The goal is to feed a lot of people and sell a lot of food! It is not a competition.
But besides the hardware differences, there are distinct differences in cooking styles. Backyard family & friends is usually a "toss it on the grill", hot & fast, and get the food on the plate. Backyard competition is a "take your time and do your best" type of contest, and only requires one or two meats, or maybe one meat and a grilled desert. The turn-in boxes do not require fancy lettuce/parsley beds of green. The cook times are only a couple of hours, so that it is easy for participants to set-up, cook, and wrap out the same day. And judging is not as harsh.
In the Pro category (what you see on BBQ Pitmasters TV), the (low and slow) cook time can be up to 24 hours. Teams arrive and set up on a Friday, begin prepping the meats and cooking on Friday nite or after midnight, and begin turning in each of 4 meats around 10:30 am, with maybe 30 minutes in between each turn-in. Meats will include: ribs, chicken, pork, and brisket.
Judging is based on a table of 6 judges. Each turn-in box is scored for appearance, tenderness, and taste. Judges will take one bite (two if they really like your stuff) and score on that basis. So the flavor profiles need to stand out and leave an impression -- so the sweetness and heat are often exaggerated in competition recipes.