I hadn't thought of paper matches in a wallet. Since each matchbook is two "sheets" of matches stapled together, it's easy (and free) to try. I would be interested to see how the heads hold up when squeezed all the time -- would the material wear off? An interesting experiment!

As for ferro rods, they're useful and fun to use. (Also they impress youngsters -- he made fire without matches!) But there are situations, in my experience anyway, where an actual flame is the only way to force damp natural kindling to burn. So, I still think of it as a backup with strengths and weaknesses.