I started out riding full face all the time, and I wouldn't have considered anything else.
When I moved to quiet town in Texas, I stopped wearing a helmet. The risk just felt too low, and riding without it was much more pleasant. At first it seemed to me that there might be some advantage to it too, as I felt much less protected. But after time, it just felt the same.
Whenever I'd leave the town though, I would wear a jacket and helmet. The roads out were all 70+ mph, and I'd probably be going somewhere with more traffic. Or unfamiliar.
The first time I went camping in the Ozark mountains in Arkansas, I wore a jacket and helmet like I always did on the way there. But on whim after finding one last patch of cellphone reception to check in with my family, I decided to drive the remaining 20 miles of quiet mountain roads without my helmet -- very carefully looking out for wild animals. The ride there was already incredible, but even so it was so much nicer without a helmet on.
Now that I live in the Ozark mountains, I'm stuck with only a minivan whose engine could well be on its way out soon with over 250,000 miles on it. *face palm*
I don't think it's as simple as saying full face helmets are safer. If it were, we'd all be driving cars. Or even staying home.