To start with, diapers are nothing compared to the dog sheets, the papers you dutifully put down and hope it uses. But then babies throw-up. Look at my car. Puppies will wet the rug if you are not quick enough. With babies, you can plan for potty training.
Puppies start right in.
Babies cry when wet or hungry. So do puppies. So do puppies. Babies don't have to be walked and run after eating. They just need burping.