I get what you're saying but I view the primary benefit of Structured Entropy to be for +damage via major sorcery, not the +hp. That would lead me toward slotting it on the primary damage bar. Unless you are using spell power potions or wearing Rattlecage to get major sorcery - in which cast Structured Entropy probably is not worth slotting.

I wouldn't be surprised if most dps magplars run spell power potions for major sorcery and boost their hp via other means instead of slotting Structured Entropy.

My own magplar is a pug healer and wears Rattlecage but does not slot Structured Entropy. That way she always has passive major sorcery from Rattlecage which also provides a shot of hp regardless of which bar she's on. But the price she pays is foregoing a different armor set. Part of my own choice is that I quite dislike relying on potions as a full time part of my rotation in combat.