Two thoughts... On this type of device.. provided they did not screw something up like Carrier did on my Air-V's if it's going to fail it will do so promptly.. If it does not fail in the first few months odds are it will last at least a decade.
That, however, does not mean it can't fail 2.5 years down the road.. Just odds are in favor of the insurance company.
Even in a worst case... Calculating the cost of a new engine on my motor home... Just about what I'd have paid for an extended warranty over the same period.
OH,,, and the check from the insurance company.... Arrived today.. It's paid for.