I strongly disagree. The intention may have been to avoid abrupt power downs but their implementation also made sure people upgraded their devices rather than buy a new battery because most people would never be able to imagine that a device could be slow because of a bad battery. This, IMO, was a dark pattern. A sudden power down would be clear indicator that something is wrong with the device while a gradual slow down of the device would seem like that the device is just getting older and needs to be upgraded to a newer one.