It's more insurance than warranty. As such, it is designed to protect you from nasty situations that may not occur. The insurance company charges a cost for this protection and on average, consumers pay for that cost. So, overall, consumers are worse off however some are much better off, paid for by the others. To those like me who do their own repair work, the insurance makes much less sense since our losses are lower. Think of it as extra protection against calamities others don't have. Example: last year I had an airbag go bad in one of the seats in my Volvo. Dealer quote was around $2,500, lots of labor to replace it. With my trusted scanner I found the culprit and for $70 installed a good used example.
Another question is whether you can afford a major loss, or not really. The decision whether or not to get an extended warranty is actually an insurance decision.