average iphone uses $0.5/year of electricity for charging. Let's assume that, instead, it will use four times as much or $2/year.
So, you get 50c electricity use worth of mined bitcoin (could be ~$2) , some gimmick like a ringtone and 21inc gets $1.5 worth of your electricity or $6 worth of bitcoin.
You broke even, got bitcoin to play with, got a ringtone.
It will be acceptable to many, assuming that it is all spelled out properly when you sign a contract.
as far as basic math skills-those people are clearly in minority, and in addition, they also don't seem to care about supporting all those ad systems on the phone, which pretty much doubles it's power use.

The point is: centralized mining system of bitfury, KnC, Bitmain, upcoming Spondoolies did not work to increase bitcoin acceptance and cannot possibly work to achieve this in the future. The independent mining could work if there are energy efficient chips/machines for it that are/will be available to miners and are on par with the best of them.

As it stands, I was saddened to find out that we were basically losing money or barely breaking even with 0.5-0.7w/Gh miners during 2014-2015 while 21 inc were mining at 0.22w/GH