Because it's already available since so long ago and everyone can't live without it. Quite true for today's lifestyle. Sometimes it is unavoidable and I have to admit that I'm using it while still finding solutions to convert to cloth with my second bub.
ConvenientI bet you know what I mean here, people nowadays use money to buy technology and convenient. Agree?
Non-bulkyAs for my case, having now 2 heavywetter babies, I experimented different types of solutions for night time and daytime. It won't last long if I never add boaster or extra doubler. Therefore, the CD (be it pocket or fitted) will be thicker or bulkier. Wool is good for heavywetter when pair with absorbent fitted diaper but wool is not thin though. On the other hand, no worry about this with sposies.
AbsorbencyI'm not sure about other brestfeed mothers but it's quite terrible for me to use CD when my baby No.2 is here as I was struggling and stress out with breasfeeding. I was so weak and tired to explore about what to use for CDing for more absorbency for my newborn (DS) due to not enough rest. (Maybe I have too many CD's options to think of?) At least disposable can be used for at least 8-10 hours without leak, so that I can concentrate to breastfeed.
My elder child (DD) is supposed to potty-train at night but since I am taking care of DS, MIL helps me to take care of her now. MIL is not really supportive on CD as those I used on my DD are too bulky for her. Maybe it's true as DD already able to tell and always asked us to take off CD at mid-night. DD sometimes refuse to wake up and pee at night, so for "safety" purpose and in order to absorb pee from a heavywetter toddler MIL uses disposable on her even during naptime.
Stay-Dry LayerI'm doubt about my DS developed very serious skin allergy when using CD in the first 2 weeks but it's fine and even better when using disposable. This must be the chemical material used in sposies that keep the bum dry. CD uses cloths and probably clothes will become damp after too many wettings. Therefore, the skin that in contact with damp CD is definitely not a wonderful thing. Frequent changing is also important even for modern CD. Do you know what they use in sposies to keep baby's bum dry?
I'm not promoting disposable diaper. I'm comparing the pro and con from both CD and sposies. I hope there are even thinner fitted diapers or inserts available so that to minus off the bulkiness. What features do you hope to have from disposable that can turn into modern CD in the future?