I dont think people not using authenticators are fools why should they need to pay extra to get security on their account on a £40+ PC game?
Ive never been hacked yet on any online game and d3 has a seperate email/pass never used for anything else, so I wouldnt be chuffed if I got hacked on it.
it's free on a smart phone or a bit of cash otherwise. It's very worth it, because of WoW and now d3 battle net id's are very valuable and hackers trying many means to get your details are rife.