Leaving the cost behind, being diaper dependent is very inconvenient from absolutely every angle.
Meet with parents? Diaper. Going out on a date? Diaper. Going to the beach? Diaper. Sleepover? Diaper. Chilling with friends? Diaper. Then all of that piled on with the relative unpredictability of a bowel movement and you are signing yourself up to be miserable in the long run. Being an AB or DL delivers the freedom of when you use the diaper and how. Carrying around a change will be a must or you'd have to wear a very thick diaper that compromises discretion. My bowel movements are on average 23 hours apart, meaning if I became IC most days would be interrupted by a big ol' dookie in the middle of what I'm doing. Doing a presentation? Going to work? In any inconvenient location for a change? What if you are standing in line for something important, the line is like 20 minutes long and half way through you have a BM? There you go stinking up the joint and all of a sudden you're embarrassed and aren't having the fun you thought you would have. There is literally no upside to becoming diaper dependent other than the excuse to wear more diapers which you can have without being dependent anyways.