It's funny. I've heard an instructor talk about "reverting to training" and such, but then recommend DA/SA pistols with external safeties, and carrying them on an empty chamber for safety.
Simplicity! Point and shoot! Small-frame sixguns for CCW, Glocks or some other pistol without a manual safety if you must have a pistol.
I agree with you to a point - right ump until the word "Glock".
Shooters revert to their lowest level of
mastered training when under stress, so sufficient mastery is important.
The 1911 and Browning Hi Power (as examples os SA pistols with a manual safety) were designed to be carried in Condition 1 (cocked and locked with a round in the chamber. Carrying one any other way is farm animal stupid, and it's not overly hard to train someone to draw, point it down range and take it off safe as it comes up to your line of sight - and with some practice that level of training is fairly simple to master.
The rest of the training revolves around putting it back on safe and getting it back in the holster after the shooting is over. With both the 1911 and the GP35, the finger needs to come out of the trigger guard and the thumb should come back over the hammer. On a 1911 this activates the grip safety and on the GP35 it will prevent the hammer from falling if you forget and leave the booger hook in the trigger guard.
DA revolvers and pistols are arguably even easier to master as it's pretty much aim and pull the trigger - and the trigger pull on both is both long and comparatively heavy, making negligent discharges under stress less likely.
The DA pistol only adds the need to de-cock it after action and you can train a monkey to do that. The DA revolver and a hammer fired DA pistol (with or without out a de-cocking lever) should both be re-holstered with the finger out of the trigger guard and the thumb over the back of the hammer. This enables the shooter to feel the hammer coming back in the event something obstructs the trigger - like the trigger finger - as the handgun is re-holstered.
The real training problem comes in to play with some examples of striker fired pistols that also happen to have all the safety mechanisms tied to the trigger.
The striker fired pistols described above are about 90% cocked after the round is chambered and the last bit is done by the trigger, so the trigger pull is lighter and a lot shorter than a DA revolver or pistol. The safety that locks the striker is also deactivated as soon as the lever on the trigger is depressed. So under stress if the shooter gets his finger on the trigger too soon, and starts pulling the first round will go into his leg, his foot or the ground in front of his foot.
That's aggravated by a few holster designs that use a release button on the side of the holster. That basically trains the finger to start pressing to draw the pistol and under extreme stress it keeps right on pressing it's way onto the trigger.
Not to mention any specific pistols, but "Glock Leg" is used to describe the results of what happens when a poorly trained officer gets excited.
Putting a striker fired handgun like a Glock away has similar perils as if the now excited shooter forgets and keeps his trigger finger in the trigger guard, when the handgun goes in the holster, the holster presses the finger, which presses the trigger, which makes loud noises and often very interesting work for the ER staff and trauma surgeons.
The Glock in particular came very popular with law enforcement agencies who saw it as a semi-auto that required very little conversion training for officers familiar with DA revolvers. Unfortunately, it's a fallacy to think that way.
A DA revolver has a long, heavy trigger pull that adds a large measure of safety, and it also allows you to cross check yourself and feel the hammer coming back if something is obstructing the hammer, so it will forgive a momentary lapse in trigger discipline under extreme stress. A handgun with an operating system like the Glock will not tolerate ANY lapse in trigger discipline EVER.
Also, the Glock was designed as a duty handgun to be carried in an OWB duty holster, where the pistol would be more likely to be clear of obstructions and can more easily be visually observed going into the holster.
It adds a whole new level of risk and training to mitigate that risk when you decide to conceal carry a Glock. You're now re-holstering it in an IWB holsters where intruding clothing, zipper pulls, jacket cord fobs, etc can all create an obstruction, as can a poorly designed soft leather holster.
If you're going to conceal carry a Glock (or similar design) use a holster with a belt clip, so that the whole holster can be easily removed to allow you to insert the pistol in the holster out in front of you where you can see it and keep it pointed in a safer direction - then re-insert the holster and pistol in your waistband as a unit with the trigger fully protected by the holster.