The two biggest threats campaigns face are phishing and attachments. There are two good ways we know of to break attachment attacks: view attachments in cloud viewers, like Google's PDF viewer, or view them on mobile devices, where they can't trivially be clicked into monstrously insecure desktop productivity applications. Of the two approaches, the latter --- sticking to mobile devices --- is the one that can be deployed with the least amount of end-user training.
I'm not sure I get the rational behind this one? Is it just because they are already using Chrome, so it's better to reduce the attack avenues?
Also, it seems to me if you need to use Tor, it's probably not a good idea to do so on your regular Windows desktop. Wouldn't Tails be better advice while also being more foolproof for less tech savy people?