Kaya Kaya no mi

The fruit name will be a shortened version of kayaku (Gunpowder)
Type: Paramecia
Operation: The user develops secretory vessels that produce gunpowder based on the amount of oxygen the user breathes. The gunpowder is extremely volatile, however, and cannot be stored for long periods of time without exploding in short bursts or one huge explosion. The user can manipulate the gunpowder produced by him/her so as to make it move in the immediate surroundings. This way, the user can keep producing gunpowder and spread it across the air without worrying about exploding it. The user can then compress all of his/her gunpowder into one attack and dish out huge amounts of damage. The user's daily life too will be affected. The user's stomach lining will have thick vessels that explode the food eaten causing the user to have a weak digestive system. The user can also settle the gunpowder near his/her elbow for it to explode later to propel his arm forward for a fast and strong punch. So, how is this idea?