I can't help but think of Android's "battery saver" toggle, which leaves me wondering why there's a battery waster feature and why it's on by default.
You really don't want it on if you expect the phone to tell you when you have a new message.
In my view we definitely need a "lazyload" attribute for script, link, and img elements.
I go into more detail about lazy loading for web fonts and images (and how I found that even resources in <body> can slow down stylesheets in <head>) here: https://hackernoon.com/dont-brake-for-fonts-3-web-performanc...