^ Yeah, combine the "very, very prefferable early worship" (so people don't really get their moneys worth if they try him out here and there after prepping/starting out with something else), obviously tangible prep penalty (in a sense that you can immagine it being a rather clear bad thing even if it turns out it's not that bad), value of wheytwut being something that's not readily apparent (visually compares badly to getindare, costs a ton of mana without killing anything) and the whole "punishments" bussines (remember, it takes a long time for a player to become comfortable with even taking one hit of any bad thing, let alone subjecting themselves to a string) and what you got is quite an unapproachable deity.
And he's actually pure killer with health guys! You basically need some experience with hum to really appreciate them, tbh, as that healthboost allows for about as much sillyness as the old absolution and he allows easy potion play. Heck, JJ Rogues work, and that's just the tip of the iceberg. Playing the PQI with having experience and knowledge of all this and not having that experience and knowledge will produce a wildly different overall experience, and you're not all that likely to go experimenting with JJ on your own on runs which allready look intimidating.
But compare the appeal of JJ to the appeal of Mystera to even moderately experienced folks, and JJ looks like a complete looser. Heck, more people on the forums got into him because of Darvin than anything reasoning of their own. While Mystera did get the occasional "I didn't prep her because I got bored of knowing I'd win" comment, and at least Tinker got her first Vicious VT token on Naga City with her. Vicious VT Naga City isn't small potatoes in my book.
EDIT: Also, didn't Darvin basically get all the stuff JJ was outright abuseable with nerfed at one point? The spellcastery stuff? I mean, he's been way sillier back in the day and he's actually been adressed as a problematic powerhouse many times, while Mystera was just considered underpowered untill that one big batch of buffs / rework and then left kinda like that.