You raise a good point. You have to be comfortable with what you carry depending on circumstances. I carry my 19 all of the time except at work. They frown on that so I comply. Can't afford ammo on welfare. But the most important thing is to practice. I used to be leary of not having an external safety but with much practice my muscle memory keeps my trigger finger on the index point automatically. Should be the norm with ANY firearm. You can get an aftermarket trigger safety. But, again, you must PRACTICE using it or when the need arises or you won't be able to get the most important round off. You will be under stress and won't have time to think. This goes with opening your gun safe, having to load the gun and, believe it or not, dialing 911. Remember, stress puts you brain into a whole new gear. Read some books by Col. Dave Grossman dealing with combat stress.
If I ever get a Glock again, it will be the 19, because out of all the semi autos I've ever owned or tried, it fits my hand perfectly, above all the others.