Having worked in hardware, I can imagine most customers would 1) push the button, then 2) complain that their battery performance is reduced.
In this scenario, have them do step 3..
3) push the button a second time.
I don't see anything inconsistent with a subscription if the manufacturer is responsible for replacing the battery during a warranty time. I prefer large ecosystems with 3rd party parts to dealing with proprietary manufacturing and warranties though.