If you were to wear disposable adult diapers 24/7 and never use the toilet again in your life the major con would be the cost of the disposable diapers throughout the rest of your life.
I'm not sure how old you are but let's say you were 20 years old. If you lived to be 80 years old you would use a lot of diapers in 60 years.
Average cost of adult diapers would be around $100.00 per month and lets say you wore diapers for 3 years you would already be spending $3,600.00 in 3 years for wearing disposable diapers all the time.
In 60 years you would spend $71,900.00 "if my math is correct" and that would easily buy a modest nice house.
Other cons would be finding a place to change your diapers and getting changed in time to prevent diapers leaking. Also smelling from poop if you poop and having to lug diapers around.
I would personally use the toilet instead but if you want to wear diapers all the time then that's okay too.
Cloth diapers would be cheaper than disposable diapers but you'd have to have a steady supply to wash them.