Favourite Wishes

[Illuminated One]

Could have something to do with the names.
Seraph sounds like a fiery overpowered angel.
Chayot sounds like a fiery overpowered chili.
Or maybe most people have got into the habit of using seraphs before chayots were implemented.
Well, seraphs can phoenix pyre which means if they are killed they just take 50 fatigue. Might not be that much worse than cheating death 3 times with another form.
Otoh charging into the fray with such a high fatigue can mean your next death is already waiting. And the chayot can do everything the seraph can , and only their first two forms have worse stats.
So yeah, I'd use the chayot personally.