A lot depends on how much you drive. I only put about 5k miles a year on my car, so it would definitely not be worth it to me.
It makes a lot more sense if you will max out mileage of the warranty, not if you run out of time, if that makes sense. Age doesn't brake cars, at least to the extent that mileage does.
Finally, they wouldn't sell the warranty if it wasn't profitable for them, on average. Economically, if you can afford repairs should they come up, you are likely benefited by not buying the warranty. If that wasn't the case, they wouldn't sell it to you.
Cars are different than houses, health, or your life. If your car has a catastrophic failure, like the engine blows up, you can always buy a beater and drive it 'til you can afford the repair. Houses and your body aren't quite as easy to live without
