Combine with floating passage to easily apply burn.
Combine with ichimonji:double to deal some big posture damage.
Combine with sakura dance to instantly deflower any foe

I think there's a sort of metaphor in using this after unlocking the Lazulite Sacred Flame, which has an increased duration when used specifially with this skill. The flavor text states he stopped using the prosthetic after developing this technique: ¨The flames of hatred had begun to manifest...¨ But the Lazulite Sacred Flame description states, ¨Cleanse the deep-seated hatred with flame.¨ By using this technique with the sacred flame, you've succeeded in extinguishing the killer's resentment where the sculpter failed to do so, therefore improving the technique. The demon of hatred is an apparition type enemy, meaning this technique is particularily effective against him.

The buff may be short-lived, but at least with Flame Vent you get to benefit from using it before getting the buff. With Divine Abduction, it takes away the 'charge' you need to use the actual tool when it creates the buff. Then again, it's still redundant anyway, since most people will use oil before Flame Vent. I guess the only point of this skill is to make combat more fluid for those using the Flame Vent & Divine Abduction.