One may argue that I take all the possible measures to thwart any possible hacking attempt, after all the root cause of hacking attempts are our carelessness. Sure enough, you are Clever. But are you confident that your friend too is taking the same precautions. What if you send a confidential info through a email and his/her account gets hacked?
In comes the role of self-destructing emails/messages. These emails get destructed automatically as per the preset time or on being read.