Honestly, I sometimes wonder if the 'flame desire' concept gets a bit overused as a shorthand for lazy writing. It's the immediate, explosive, lust-at-first-sight thing, right? The way it shapes relationships is often by creating this intense, almost fated, chemical bond that the plot then has to work around. The characters are pushed together by this undeniable physical force before they even know each other's middle names.
This creates a specific kind of tension—the 'will they/won't they' is already answered, so the conflict becomes 'should they/shouldn't they' given all the external or internal baggage. You see it used heavily in mafia or billionaire romances where the social power imbalance is huge, but the flame desire acts as this great equalizer, making the otherwise predatory dynamic feel consensual and magnetic. It's a tool to fast-track intimacy so the story can focus on the emotional fallout.
But it can backfire if not handled with care. When the desire is the only thing holding two people together, I lose interest fast. I need to see the scaffolding of a real relationship being built around that initial spark, or else the whole thing just feels hollow once the lust cools down.