Many heaters brands are like that. If you're willing to pay more, they will take the money. It's insurance.
And it's not like you get a new heater if it fails. (labor is never included), it's pro rated out depending on how many years you've used it. You will recieve a percentage of of the expected life that you insured it for.
I find that most 6 year tanks can last 15 to 20 years in the Seattle area.
I've seen pictures posted here, of heaters that have limed up in other parts of the country. Not failed, just full of deposits.
The heater you are replacing went 16 years. That's pretty much expected. If your heater came with the home, it was most likely a six year heater.
There are some that I can get that do have the extra anode, not just the sticker.