The appeal of the GBIC standard (and hot-swappable transceivers in general) in networking equipment, as opposed to fixed physical interface configurations, is its flexibility. Where multiple different optical technologies are in use, an administrator can purchase GBICs as needed, not in advance, and they can be the specific type needed for each link. This lowers the cost of the base system and gives the administrator far more flexibility. On the other hand, if a switch will mostly have one port type (especially if that port type is copper) purchasing a switch with that port type built in will be cheaper and take up less space per port.