At least in the UK, AppleCare exceeds the service requirements of the warranty. If a component fails through normal use, the warranty has you covered. If your case is cracked because you dropped your laptop, warranty might not cover it but AppleCare will.
Or your house insurance will cover accidental damage (as well as theft of your bag on a train/in a cafe, etc).
I was delighted when my house insurance bill went down considerably, because my newer Macbook was worth just less than £1000, where the previous one had been just over - meaning it became covered by the policy without a separate declaration, and an additional fee.