To me, the primary purpose of a larger capacity magazine is for carry as a spare. For a decade or more, I carried a Kel-Tec P32 with its standard magazine in a breast pocket, and a 10-round spare magazine in a side pocket. While I cannot imagine an extended fire fight with a "mouse gun," I would rather have the extra rounds and not need them, than to need them and not have them. I now carry a Kahr P380 and no extended magazine is available for it, and sometimes wonder which is the better choice, more power or more rounds.