You obviously haven't been paying attention to how her passive ability is causing problems, so I will spell it out for you. Most her party is crushing on her in a bad way. If you choose Panki route, she is constantly trying to innocently corrupt Sparkle into new fetishes and is perfectly okay with the idea of a harem as long as Roopah isn't a part of it. Roopah herself is pining for Sparkle like a tsundere schoolgirl who can't confess her feelings to her crush but slips major hints of her unrequited feelings. Roopah route is pretty much her being possessive of Sparkle but still afraid to embrace commitment. Panki avoids Sparkle because she is the one longing. Lel is least affected by ability because of her origin. Harmony is unapologetic about her attraction and is the only one willing to spell out to her how much the party both loves and fears her at the same time. The last example of Sparkle being overwhelming in her passive ability is her affect on demons. Every demon she has met wants to posess her with every fiber of their beings and will do anything to insure this. (Which is further evidence that her presence is actually corrupting Panki.)
I've been paying attention. That's exactly WHY I said what I said.
I get that the passive should/might have an affect, but there is a "take it or leave it" vibe I get from everybody's dialogue around her in the general gameplay.
The mixed but powerful responses folks have usually seems heavily to be "WTF she is powerful!", and oft crossed with "wow; she is actually being nice to me, when no one else usually is". That is a powerful combo, but not inherently indicative of a passive buff causing arousal.
More, her standing up to Kay to support others, is bound to have an effect. If the others were cowed, she helps them break out of it and stand up for themselves, likely at least partly because she initially has a "player perspective" of not really being that bound to consequences (aside from getting fired, ofc). That changes later, but even that only serves to strengthen her resolve to be nice to ppl, which has REAL-world charismatic effects, beyond any game mechanics.
As to the party..
Roo is known for "going there" anyway, with any gal. Kay warns Sparkle of it, right off the bat, yet Roo actually holds back!! That is NOT suggestive of an arousal buff. Love and lust are NOT the same thing.
Kay himself is indifferent, balancing on how you interact w/him.
Leigh DNGAF, either. Mostly fixates on Kay.
Panki, it could be she is affected, or she could just find a hot lass hot, especially one who actively gives her emotional and moral support.
Wejit started charmed. And he's a freakin' gobbo. Yet still restrains himself in most branches I've tried.
Harmony, she flat-out MADE. By accident. There has to be a LOT going on right there, just from that. That also is part of why everyone is terrified/somewhat awed of her (even if they d/n admit it): she flat-out, and on the fly, raised dead/created actual life out of a skeletal enemy.
Champ... He's had his share already. And he keeps on rolling past her after. And spends his time w/Twig.
Twig d/n seem predisposed yet. Haven't looked into it. Obviously she rolls w/Champ.
Lel is Lel. You know the deal.
Jane.. IDK yet. So far she just flaps around.
Demons definitely do note something, but their discussions always seem to be directly abt them sensing her power levels (generally related to how well she heals, or to her well of available power, or perhaps even a bit of her being a player), and, IIRC, it is later noticed (when she is re-captured in some choice branches) that she has been nerfed. I get the impression they just want to steal her power. I could well be wrong, but that is totally what I got from the extant dialogue.
IMO, if her ability were that noticeable, bandits would not be having other agendas, but they usually do. Most scenes w/VERY morally questionable folk who have ZERO reason to restrain themselves still generally have rather neutral/standard responses to a very physically attractive and incredibly suggestively semi-dressed obviously noncombatant/seemingly physically helpless girl, unless SHE initiates activities. That does not track w/her having a constant a passive buff to physical interest by otheres to her, unless it is very minor.
However. .. It COULD very well be exactly that negligible... for a 1st lvl toon in a MMO. That WOULD track. 1st lvl buffs do often suck on toast.
(Edited a lot, as had to clarify some things and clean up presentation)