2. It is not unusual for a person who is carrying an illegal handgun to not use a holster. ....
The criminal logic is that if you are chased by the police and ditch your handgun, you don't want them to find an empty holster on your person.
While some honest people forgo a holster most use one. It only makes good sense as long as the holster is designed for your handgun.
A good holster is a fine safety device but a fool may be able to defeat it and shoot himself if he fondles his handgun while in the holster or pulls the trigger while removing the weapon from the holster.