I like not having pee or poop running down my legs when I have accidents all the time due to my bladder and bowel incontinence. It is much less embarrassing to wear a diaper and keep all of my accidents contained.
For me it's comfort and convenience. It's relaxing to wear them, they are a stress relief mechanism for me, and they are very comfy, like sitting on a cloud. I'm not a fan of messing, but it's nice to not have to get up and pee when I'm trying to focus on/ do something.
I'm not a bed wetter, but have always had fears of wetting if I don't go pee every time I wake up. I enjoy the compression of a tab-style diaper and the feeling of going back to sleep when I awaken. I never wet the diaper as an accident (if I'm awake and really have to go I enjoy the warmth and go back to sleep), so I am unsure why I have bedwetting fears. They're anxiety inducing, and wearing helps alleviate that fear, making my sleep 20x better.
I love the padded feeling and crinkle of the plastic. I only wet occasionally when the mood hits, and rarely poop and that is only on accident. I also love wearing them because I am an adult and I can. My parents convinced me to wear big boy pants as a child, but can’t now.
It's been over 10 years now, but I had seen a pic of a guy in some cute pullups for girls in a super cute baby print. They looked like some cute fem panties and I had to try them since I was into CDing. Bought a pack and rushed home to try one on. Loved the nice and tight and cute look. Was enjoying going about my day and loving the feeling of them. It had been awhile and finally needed to pee, so thought what the heck and relaxed and let it flow. WOW, that was amazing. Almost orgasmic in how it felt and I knew I was hooked from that moment on.