That's a pretty interesting take. It strikes me as a little heavy-handed (you don't get to choose when the move is rolled, and then, particularly on a 10+, you get very little say in what your character feels and does).
Paul, I think you've 100% misunderstood how the system is constructed.
The beginning-of-session move grants hold, which both the player and/or the MC can use. So for instance, the BOS move might be 10+ you hold 2, 7-9 you hold 1 and the MC holds 1, 6- the MC holds 2. Spend your hold one-for-one to bring your Tragic Flaw into play.
In this way, if the player succeeds, he or she gets control over how and when the flaw comes up, whereas if he or she fails, the timing of the flaw is in the MC's hands.
When it comes to the move for the flaw itself, read the options again: they all say, "you
don't do X..." which means if the player rolls a 10+, they manage to resist their base urges. But they also don't get to mark experience. On a 7-9, they are forced to do one of the things on the list. On a miss, they are forced to do 2 of the things on the list, but they get experience.
Example: It's halfway through the session, and the MC is still holding 1 against Sir Ian the Chaste, who (incongruously) suffers from the fatal flaw of Lust. Heading into a new scene, Sir Ian and his compatriots visit the royal court. The MC sets the scene, and in doing so introduces a new NPC, Princess Miriam, describing her as a pretty, raven-haired, doe-eyed beauty. He also spends his remaining hold to invoke Sir Ian's lust, and names the poor Princess Miriam as the object of said lust.
Sir Ian, not the most socially adept, is Hot-2. He rolls, and unsurprisingly gets a 5. He is now faced with a choice; Sir Ian's player decides that maybe trying to lure the Princess into a nearby alcove and have his way with her right here at court might be more trouble than it's worth (especially since he's so socially maladroit), so he chooses
"you don't immediately try to seduce the object of your lust" for his one pick. But that means that he
does forget all about whatever it was he was here to do (spy on Baron von Hagen, who the PCs are pretty sure is "Up To No Good (tm)" - which is problematic because Sir Ian has the highest Cool in the party, and thus the best chance at being a successful spy), and he
does pick a fight with a perceived rival (the dashing but confused Sir Humphrey, who unbeknownst to Sir Ian, is as queer as a three-sided gold-piece and actually has no interest whatsoever in the princess).
I'd say that it's up to the PC just what "picking a fight" looks like (perhaps he engages Sir Humphrey in a battle of wits or social graces, or maybe he just straight up challenges him to a duel!), but the point here is that he's trying to make Humphrey look bad/stupid and score points with Miriam. But note that nowhere is it mechanically encoded or enforced that winning (or losing, for that matter) this fight has any tangible effect on the object of one's lust - even if Sir Ian the Chaste is successful in making the poor Sir Humphrey the butt of his jokes, Princess Miriam might view Sir Ian as the worst sort of boor for doing so. But that's OK, because these are
tragic flaws.
And best of all, Sir Ian the Chaste's player is mechanically rewarded (he gets to mark experience) for his flaw.
Does this make more sense?