Can only comment on my one and only experience using the RAC warranty, I had an Audi A3 which I took in due to the brake pedal feel and auto hold sticking.
The RAC Approved Garage diagnosed this as a faulty brake servo which they replaced (Large job apparently, they said despite the job sheet it took them 12 hours as they had to take most of the car apart to get to the servo etc) I left the car with them and was given a courtesy car and picked it up a week later, nothing to fill out and nothing to pay.
From talking with the garage it appears they diagnose and have the work approved by the RAC beforehand but it’s one of those where it’s in the interest of the garage to do the work so imagine they will word things in a way to ensure it’s approved by them. He practically said any more warranty work feel free to come back with a grin on his face so imagine they cashed in on the job!
Although I bought a new car and a week later noticed a line of dead pixels on the infotainment and after going back to the garage since all vehicles approved and come with 3 month RAC Cover they then explained RAC would only stand to £500 for infotainment so in that respect it wasn’t worth having on a car with Digital Dash where the part is £1000 itself for example which is why I’ve since extended got VW Warranty. Although they agreed to swap the infotainment with new and stand to the difference but I was happy for them to take it from another identical car they had for sale for a quicker and cheaper fix for them, all I was interested in was the same Infotainment screen with no dead pixels.
But mechanically it appears it covers most major items which is all listed under the cover levels I believe.