There's tons of stuff they sell in gift shops that you don't need on the plane. The bookstores sell porn, shops sell power adapters, bottles of wine, cartons of cigarettes, jewlery and clothing you won't be putting on, etc.

Lifting the lighter ban is consistent with TSA's risk-based approach to aviation security. First and foremost, lighters no longer pose a significant threat. Freeing security officers up from fishing for 22,000 lighters every day (the current number surrendered daily across the country) enables them to focus more on finding explosives, using behavior recognition, conducting random screening procedures and other measures that increase complexity in the system, deterring terrorists. The U.S. is the only country in the world to ban lighters – all other nations, including Israel and the U.K., do not.

I believe books of matches are limited to one book on you or in your carry on, but lighters don't have that restriction.

And of course, some airports have smoking areas, so you may need the lighter there before you board.