The key ingredient seems to be the Salicylic Acid. This is the same active ingredient that is found in wart remover and other OTC remedies.
It speeds the healing of damaged lips (chapped, cold sore, etc.) by causing the old damaged skin to slough off faster than it normally would. This seems to make your body respond by building new (healthy) skin that comes up underneath the damaged skin.
It's marketed for cold sore relief, not for daily prevention of chapped lips. Also, I don't use it as a preventative so I can't comment on alleged addictive properties.
In addition to the SA, the slight butterscotch flavor, and camphor tingle are nice too.
In over 20 years of use only once have I succesfully used up a whole tub of the stuff before losing it.