I did this for my parents, but mostly to save bandwidth. They live far enough out of town that they can only use Verizon LTE. It saves them over $100/yr.
My parents live rurally where the only options are satellite or a rooftop 3G antenna with flakey and expensive 3G data. Adblocking has been a huge deal for them. Saves money and speeds up page loading dramatically.
Holy crap. Assuming no other change in behaviour - I wonder what they're yearly value is to ad networks? Maybe a couple dollars in comparison?