I agree, but given Apples current solution to KB issues is compressed air cleaning the chances of "Dust" etc in your KB can only increase over timeI am not sure a failure is less likely to happen during the AC coverage period.
The 2016 and 2017 MBPs are all within the 3 year window for AC coverage. There are 3 class action suits in progress regarding the keyboard for the MacBook and 2016 and 2107 MacBook Pro models with the new keyboard. So there the need for the keyboard replacement does not yet appear to be a function of system age. And AC can cover you from an expensive keyboard repair in years 2 and 3 of ownership.
It may turn out the frequency of the problem increases as the systems age, like the 2011 MBP GPU failures. But, only time will tell.