Yes, you were able to use them on Y and B fares, although those fares were often more expensive than non-refundable first class tickets. My wife was able to use several during a non-status period when we were rebooked from DL to AA and the AA reservation was booked as a Y fare. They should also be useful to non-elites if traveling with a companion with status. And I believe at one point AA let you exchange them for something like 500 AAdvantage miles.
But these were/are pretty rare circumstances. I had four "stickers" that sat orphaned from 1999, when I was Gold for a year, until 2010 when I regained AA status.