The only way I use "Friends of Friends" on facebook is for setting a post's audience so the grandmothers can share the grandkid photos I post with their circles of friends. Pity I can't set this from the Android app (Facebook, are you listening??).
Anyways, like the author I'm not much interested in what my Facebook friend's friends are doing.
You remind me of a frustration I have with. Urrent facebook UI.
I only ever share posts either publicly or to a named small group. ("Photos of Bob").
It's gently frustrating that the list for sharing is populated with auto-generated groups that I have never, and will never share things with, and that getting to "photos of bob" takes extra clicks.
Anyways, like the author I'm not much interested in what my Facebook friend's friends are doing.