There is a extremly large difference between passiv listening and recording everything and cleverly hacking the Signal app, or even forcing OWS to do it for them. The cost differences alone are massive, not to mention that its harder to do while remaining hidden.

Yes its not perfect, but calling it a illusion of safety is just overly negative. If the NSA really wants you, they will get you, but that does not mean all your safty is illusion.