The Mailbox is considered the best is an app for handling email. But the Mailapp gives something more than what the user asks for. App Developer Subhanshu Behera explains the same about the Mailbox,
I love iOS apps and developers. And it’s the apps that I love motivates me to write better codes. However, Mailbox is an exception. I like the UX of this application but I dislike its data protection approach more. As a matter of fact, there’s no data protection at all.
it gives you more, it gives you access to an application’s Document and Library directories on your devices. These are the usual places, where iOS developers store their database, plist files or other resource files and can be extracted to a system if device is stolen
It’s all about adding few extra lines of codes to their iOS app to increase the security level. iOS SDK gives a developer a list data protection APIs