They can carry multiple artifacts, even on official, and provide hypothermic insulation against the cold. Literally a must have for running artifacts if you plan to spam run boss fights for element. 10/10 would smash again.
Idk y but no one has written about how to use them to get black and silica pearls.
So to get pearls u have to keep them on aggressive and on follow and let them attack fish like phirana etc but sometimes it doesnt work with normal fish called coelaths. And to get pearls u have to let them kill the fish by which i mean u have to let them last hit them and by then they will have pearl (1 or 2 of white and black or either one of em) in there inventory.
So I prefer goin for phirana and sabertooth cause they r agrressive and chase u till the shore so use that chabce to kill a lot of fish by otters. I hope i helped many which were having confusion like i did.
Level melee for it to keep you warmer/cooler(idk why) more melee=more insulation
Level weight for storing artifacts inside it it can carry multiple artifacts and is the only tame able to do so also hide your bps inside em when you get raided only soulless people would kill a passive otter