The issue of the so called "extended warranty" is one that is a frequent topic of heated debate in the RV world. It is a very complicated question and not really well understood. What the policy really amounts to is a health insurance policy for the RV. Like any type of insurance, it will only rarely pay our more than the price of the premiums, unless you happen to have a major repair beyond what is considered to be normal. Just as "home owners insurance" on your house nearly always costs more than you get back, the purpose is to protect you in the event that you should have a major loss. No business can continue to exist if they pay out more than they take in for the majority of customers.
Let me suggest that before you make this decision, you would be well to read
this article from Escapee's Magazine which addresses these contracts and how to determine if you should buy one and what to look for in the event that you choose to do so. The purpose of insurance is to protect you from a major loss that could be a financial disaster, but it seldom will save money if you don't suffer such a loss.