Well imagine if you could have lists marked as “for sharing” or “for trade”. Those could be matched with wish lists by people nearby. Or lists by people form area you’re traveling to. They could make tasting lists which could be modified by group of people i.e. tasting group. You could let your tasting buddies pick beers from your “for sharing” list.
There are so many possibilities here. It’s just matter of direction you want to take.