I had a friend who looked 30 when he was only 16. He helped us net in sooo much underage drinking it was criminal.
Is that the kind of benefit you mean?
Never had a FWB, and if current trends continue, I probably never will.
Seems to be mostly trouble from what little I've heard from friends who have gone down that path [one in particular who is currently going through the awkward stage of FWB-lust]