I would agree, adult sized diapers are better than underwear because of these factors and here are my five reasons for wearing them.
(1), Comfort you can easily change out of a diaper whilst you can't with underwear if ypu have the odd embarrassing accident, also another plus factor is the padding feels so much nicer than fabric, and cycling is another plus factor because you have no more unexpected pee breaks.
(2), constriction underwear can be constricting or top tight and this will have a negative effect on your health as it will restrict the blood flow and this is not good for your over all health as specially the heart if the chest is too tightly constricted it can kill you so diapers are a much better choice.
(3), Convinience it's much better than having to dash to a dirty/unhygienic public toilet and they and as for diapers well there much easier to carry in a day bag, and work is more productive because you don't have to stop until you finish for the day.
(4),With diapers it's easier to relax and feel like a care free child again and this is a major benefit if like me you have psychological issues or simply just want to feel happy again after a hard days work.
(5), diapers aren't cheap but the benefits of having them are so much better than the cons of not having them as there's no more worrying at nights because you and your clothing is protected not to mention the bed is cleaner no more embarrasing pee stains.
Yours sincerly
Chinababy888.