It isn't combat training, though a lot of gun owners are ex-military and ex-law enforcement. It is usually training to get gun owners familiar with their weapons and to get them accustomed to it.
People who carry are very familiar with their guns. They typically shoot them regularly. They are used to having it strapped to their body for many hours a day. It becomes automatic to be able to draw the gun if needed.
Yes, new CCP owners will be a bit awkward with their guns, but those are the exceptions and not the rule with most people who have CCPs.