The “bounty” system is not fulfilling its intended purpose I agree, nevertheless it fulfills other purposes well still:
Namely placing even the minimum bounty enables you to get notified by CONCORD whenever your pal or enemy loses his/her ship, a great opportunity to drop them a mail or just smile may the “victim” be a friend or enemy. In case of friends or people you know it can lead to a fun conversation and learning an interesting story about how things went down, in case of enemies it can be a relief knowing they lost their junk especially if it was an expensive junk. Often you can look up the kill on zkill too for extra info and funfacts.
The other is it shows your interaction with others. My Jita thief alt has over a billion bounty and it somewhat shows how successful that alt is at its job, obviously most people don’t bother to put a bounty or just a minimum bounty at best, still or even especially because of this reaching that amount is a true showcase of fun times and player interaction.