This is the classic problem of paying up front for services to be provided later. It reminds me of Wimpy in the Popeye cartoons – “I’ll gladly pay you tomorrow for a hamburger today.”
The problem is that if the home warranty company breaches (after you or seller pays them) you have to pay for arbitrators or litigation to get what you bargained for. Which will always cost more than just doing it yourself. I generally won’t pay for a warranty (or insurance) unless it is so cheap it doesn’t really matter or it would be worth litigating if the warranty or insurance policy were breached. Otherwise, there is little motivation for the company that has already collected the money to pay for your repairs.