Some excellent points have been made above. One in particular, mentioned by "MrsFosforos" and "robertmeco," in favor of providing some retention by form fitting a holster is that, otherwise, with a pocket weapon carried every day, "Murphy's Law" would eventually result in the pistol's falling out of the holster and onto the floor/pavement/whatever as the rig is removed from the pocket. (The one time it happened to me years ago with a Guardian .32 in a pouch-type pocket holster, I had the good fortune to be standing on a carpeted floor and no damage was done to the pistol.)