Research is good
Sounds like an attempt to backport some of the optimisations used in WebP to the older format. Google definitely favours WebP for images as it is a single format that does both lossy and lossless compression well and supports alpha channels. Unfortunately, there are still holdouts against WebP: Apple and Microsoft unsurprisingly but disappointingly also Firefox, though it supports the parent WebM format.
As for economies: I think Facebook did the numbers about the money it saves by compressing images as much as it does and it's more than you think.