With Immersive Ignitables you'll need a lighter or an open fire to be able to make use of certain items.
Smoking also becomes more immersive by applying additional visual, particle and sound effects. You will now exhale smoke after taking a drag and depending on how long you inhaled, you will exhale smoke for a longer duration.
Ignited items will only burn as long as they are actively held or dropped on the floor. They will extinguish when they come in contact with water or when stored in your pockets or another container.
More details on the mod page:
https://steamcommunity.com/sharedfiles/filedetails/?id=3217556378
