This is still worth doing occasionally on Windows, but iOS users have never had to do this, and there's been no reason for Mac users to do this since the System 7 (pre-Mac OS X) days. Some habits die hard, though.
I managed a big fleet of iOS devices (hundreds) around the iOS 6 to iOS 10 time period when battery drain was a common complaint (https://news.ycombinator.com/item?id=13054056). Completely wiping the phone and setting it back up without restoring the backup fixed those battery drain issues 100% of the time. If you wiped the phone and restored the iCloud backup the battery drain would persist because you restored whatever glitched config file was causing it.