Depends on if diverting the narrative and/or expending party resources would be considered a negative in CapnZapp's game. From the overall tenor of his posts, I think it might be, but of course I can't know for sure.
A bit too many double negatives there for me to follow, but I think I should say: yes
Diverting the narrative isn't a cost that makes my players avoid power-ups. My players are generally fine with the story taking whatever path, as long as it gives them opportunities to excel in combat.
The sure-fire way to make my players
avoid something, on the other hand, is if it represents personal failure on some level, with the ultimate cost being permanent penalties (fewer hit points, lower attack bonuses, etc).
Even "your character is dead/retired" is preferable to having to keep playing a character below maximum efficiency. There is a reason players dreaded "level drain"...
So a "cost" of "as penance you must slay three dragons" is considered a straight reward.
A cost that says "this item carries a 15% risk of permanent, non-removable, -1 proficiency bonus" would be avoided like the plague.
Since I know this, I don't want to offer narrative costs, and I don't want to slap permanent penalties onto characters either. Losing the character seems like cutting directly to the case and offering a compromise.
Before we ended the session it seems there were three players interested: the barbarian, monk and rogue. The paladin abstained because that character is so clearly anti darkness/evil/undeath. The druid abstained simply because none of the three ability scores were among his desired trio (Dex, Int, Wis) and because he already got flight. The sorcerer was on the edge (or gave an unclear answer).