Typical apple dick move. We all know that this is just a P.R. excuse they're using because they got busted. The only reason they would slow down the cpu is pure greed. It's just a ploy for them to force you into purchasing a new device because they know you're neck deep into their ecosystem.
In my case, after installing iOS 11 into my iPad Pro (2016), the animation seems very jerky whereas the previous iOS 10 was smooth. If the battery presents to be a problem in the future, they should let customer change it rather than slowing down the cpu. In the future, if this same phone or iPad will still have the cpu throttled regardless if it had been replaced with a new battery.