On 11 Jan 2018 18:35:16 GMT, Jolly Roger wrote:

The feature in question prevents spontaneous shutdowns of devices with
dying batteries and extends runtime.

"In other words, Apple decided on behalf of its customers that they'd
prefer an iPhone that performed worse for the same amount of time,
than an iPhone that performed just as well for a shorter amount of
time. It's a decision that does nothing to dispel the characterization
of Apple as a company that does what it can to push customers into
buying new phones."
https://www.theverge.com/2018/1/11/16878412/iphone-slowdown-battery-replacement-wait-times-6-plus-supply-shortage