The very drawback of these apps is that you have to have each side of the conversation using them, and that's not going to happen often.
I see no point to them, really, just because the nature of my texts and phone calls are so utterly innocuous. If I were discussing trade secrets, corporate planning that would be very damaging were it to get out, or something of a similarly private nature I'd probably insist that my communication partner be using something like this due to the sensitive nature of the information being exchanged.
I just don't think that anyone is really interested about whether I'm getting together with friends on a Friday night. Even if every last one of my texts and/or calls were to be passed through some sort of electronic screening I doubt that any of them would ever be passed on for actual human examination. I also don't think that I am being perpetually watched intensively in any way, nor are the vast majority of people.
The above being said, I have nothing against using end-to-end encryption if that is something you want to do. I just don't feel the need for myself.
Brian AKA Bri the Tech Guy (website in my user profile) - Windows 10 Home, 64-Bit, Version 1803, Build 17134
. . . the presumption of innocence, while essential in the legal realm, does not mean the elimination of common sense outside it. The willing suspension of disbelief has its limits, or should.
~ Ruth Marcus, November 10, 2017, in Washington Post article, Bannon is right: It’s no coincidence The Post broke the Moore story