Both are mediocre. Sure, the skills convert nicely but the rest of the nodes are either useless (elemental damage, meh) or worse than what you will find in physical devotions. I have made a couple of beronath builds and I ended up taking oleron + matron (it works, try it) because without them my physical damage bonus ended up lower than I was confortable with.
Leviathan is actually pretty good but Whirlpool despite being good is weaker than Meteor Shower
Can make it work pretty well with Leviathan but you’d castrate yourself trying to make Elemental Seekers work (against the end game)