OK, I'll be the desenter here...... Not meaning to cause ill feelings toward anyone who uses the finger on the trigger guard, but, when I taught my classes I preached against it. Have you seen what usually happens when someone shoots a pistol that way. The finger usually comes off of the trigger guard. It will actually slow you down as you readjust your grip and replace your finger. I have seen some use it to move the front end of the pistol, but that is improper grip and time consuming. Works great until those targets pick up a gun and shoot back and you have to shoot fast.
At one time, back in the 70's and early 80's it was envogue to have a finger thingy on the front of the trigger guard, so everyone started putting them there, whether they needed them or not. It was just that the "shooting public" had to have it. Notice, most 1911 guns don't have the checkered area anymore. There's a reason for that. The guys who usually shoot the 1911's in compatition or for service use, don't need'em or want'em. Some manufacturers are starting to leave them off of the guns now.
I find most NEW and untrained shooters will tend to use the finger on the front of the trigger guard, because it has somewhat of a level of comfort and they figure it's there for a reason, so you must need to do it. But a good, solid grip, shoved up high on the grip frame, thumbs held high, thumbs pointing foward toward the target, is the proper grip for fast, accurate, and recoil controlled shooting. The idea is to get as high on the grip as possible (the real reason for a beavertail) and fully wrap all fingers around the grip surface area, then use the second hand to firm up and support that grip. When you remove one finger, stretch it out and place it on the front of the trigger guard, it tends to make your grip weaker, by opening part of the hand and insome cases reaching the grip around more just to reach the hook. This is not proper combat grip for shooting in self defense or under stress. Try both and tell me I'm wrong. Watch guys like Jerry Miculek or Doug Koenig shoot in competition and tell me how they grip the gun. If you ever see footage of professional SWAT/ Tactical shooters, you don't see the finger around the front of the guard. There is a reason for that!!! You may find the rare occassion of a pro shooter who does, and maybe grew up shooting that way and made it work, but those cases are rare.