For me, I love diapers for multiple reasons, one of them being how soft they can feel around my more sensitive parts of my body, as well as they can soften wherever you sit too for more comfort. I'll also admit that I like the feel of the extra bulk around my rear end, as they give me a bottom heavy-ish feel that I enjoy sometimes stroking my hand over my big padded rump. :wub:
As for the use of them, I actually only use them when necessary, mainly when I can't readily access a bathroom, or when there's something I definitely can't miss. When nature calls and you can't find any bathroom to go to, it's a very liberating feeling to be able to relieve yourself and not be stressed about having to hold it in until your insides start to cramp! Not to mention when I'm sick and my bowels aren't agreeing with me, I can be very thankful when I have something to make having a messing accident not a disaster for myself.
To me, diapers are a more functional form of undergarment, making the essential necessity of ridding your body of waste material less of an impact on one's daily routine in life.