Convenience is exactly what I use in my real life. My texting security is whatever Apple implements in iMessage. I'd be a lot more paranoid if I were a "smuggler" or "revolutionary".
There's also the wrench cryptanalysis discussed in xkcd.com/538. For most people the mouseover text nails it:
Actual actual reality: nobody cares about his secrets.
The fact that you can't have complete security is not an argument for abdicating the effort, nor a valid criticism of anything that moves in the right direction. At least you can get to a better position in terms of (a) lower probability of compromise and (b) imposing more time and expense on the adversary.
And beyond source-code:
How do you shield your equipment? (tempest, also active attack)
How do you guard your equipment? (evil maid)
Real life is the triumph of convenience over security :(