Sophisticated attackers target everything. Desktop Safari is a much softer target than Mobile Safari, and, while flagship Android devices can be made asymptotically as secure as iPhones, the median Android phone held by a campaign staffer is much less secure than the median iPhone, which is something you quickly discover when you see the menagerie of devices campaign staffers use.

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.