I'd rather have my "sensitive" data compromised than have some multinational advertising company that has been compromised by every major government on the planet have access to me at any given time.
And its as annoying as having someone stand in your kitchen every morning and say "A bowl of bran Sir, its good for you, best thing to eat Sir, other options are inferior". I hate Bran, I'd rather eat toast, I'd eat fruit, I'd rather wait till lunch time. But that butler person won't go away, he shows up at lunch time, an dinner, and when I just feel like a quick snack down town.
I don't care how much better it is for me, I already know, I just don't want it.
And lastly, if someone steals your phone, with your a mail client on it, it is way easier for identity theft to occur, not harder.