It's a good question. I guess all I can say right now is, that is how I was taught to land. For me, that is the normal pattern.
I went through two phases of flight instruction. I started off in the 150 with "instructor #1". He taught me to fly the PAPI lights. After I did my long x-cntry, I took six months off (it's a long story). When I came back, my first instructor had taken a new job. I started flying in the 172 with "instructor #2". He taught me to fly the power off approach. It was a big adjustment, but he drilled it in to my head rather well, and that is the way I fly now.
Regarding straight in landings, I struggle with those right now. Because of the way I have been taught to fly, I am constantly coming in much steeper than the PAPI approach angle, so the lights are always white.
There is another problem...