Warranties are about protection from manufacturing defects in new products. The manufacturer approves and pays for repairs at authorized service centers, usually franchised dealers for the brand.
Extended warranties are pre-paid service contracts, sometimes also sold as insurance, since the programs are often funded like casualty insurance. Some cover a wide range of service providers, others are restricted to a network of dealers or repair services. Pay close attention to this when you buy.
Repair shops generally do not recognize extended warranty policies as first payment. You are responsible for paying your repair bills, whatever gets reimbursed to you by the service policy is up to the adminstrator of that extended warranty. Many are restrictive, and may not pay for any work they did not pre-approve. The estimate and approval procedures are a PITA for repair shops generally, so they are even less happy with these programs than medical practitioners are dealing with a multitude of 3rd party insurers.
These extended warranties or service policies are sold as one of two general classes. One type specifies what is covered (and exceptions), the other specifies what is not covered. The latter tends to be more inclusive, but more expensive.
You need to way your repair cost risks against cost of this "insurance" while considering what is actually covered. For a towable RV, there is often very little covered, that might not be otherwise covered by casualty insurance, or repairable for less than the premiums.