If you look on here right now they are saying that they are a waste of time but there was a recent update for them in the quality of life update makeing them 6 hour tames instead if 30 minutes hope this helps
With the update the buff lasts 6 hours. HOWEVER...
if you fast travel with a bed, you lose the buff
Liopleurodon is also aggressive to tames. It has the same ocean depth cap as a tuso (so it won't chase you to the surface) but it is passive if you're swimming
Wow that one tip about how Ark sucks went down hard. Lol. Ark is awesome and the devs were just making a joke with this creature. If you want to downvote the Ark-hater’s tip go all the way to the bottom of the Liopleurodon “All tips” page. Lets see how low we get!
The time that you have it tamed for is still 30 minutes after the update, the difference is that the mystic skin oil buff lasts 6 hours, and you lose the buff if you die, and only regain it by going near the liopleurodon again before it disappears