@DanTSX:
We can keep our fingers out of the trigger guard. However, sometimes foliage or debris can sneak into the trigger guard even if our fingers don't. All it takes is a stick caught in my holster, shirt, or belt to sneak into my trigger guard and then the gun will fire. Every time I holster a striker fired pistol I can't help but do it slowly and delicately.
I understand some people aren't as paranoid about debris as I am. But, I think the risk of a hole in your leg warrants the caution. I admit that I wasn't concerned about this at all until I started using holsters to do drills on the range. I used to just unload the gun put it in the box or on the table and then pick it back up when I was ready to shoot again. However, putting a loaded pistol into a holster while it is pointed at my leg is completely different and fills me with trepidation. If I could I would like to be able to put my finger behind the trigger, but then I couldn't get the gun in the holster.
Double action guns solve this issue by giving the user a way to both block the gun from firing and warning should the trigger begin to be pulled (whether it be by the trigger finger or something else). I can snap a stick in half with the trigger on a DA/SA gun as long as my thumb is on the back of the hammer. That fills me with a substantial amount of confidence compared to when I holster a striker fired pistol.
Also, this technique allows you to safely holster a gun even when your eyes aren't on the gun and holster. Why would I do something unsafe like that? Well, I'm not in law enforcement but sometimes you might want your eyes looking at something else while you put your pistol away. For me, I just like the fact that I don't have to be as cautious with the pistol when I put it in the holster (which I have to do dozens of times while I'm practicing).
The vast majority of guns I own are striker fired. But, that is just because that is all that fits me. The DA trigger reach is too long for me.