It occurred to me that the earlier systems with numeric keypad controllers were mainly using the pad for menu screen and pause options. I know, this is probably obvious to most, but the menu picks and pause options were later made up through mini operating systems built into each game ala memory that was allocated to in-game options. Think of the title screen menus that became standard with Master System and NES. Was memory at such a premium with the earlier consoles/games that the numeric keypad was an absolute necessity? Could an in-game option select menu have been included in INTV, Arcadia, 5200, and CV games without being too big a hit to the memory allocated to game play?
Notice in all this I have not discussed Jaguar yet. It obviously differs from the rest in that it mapped numeric keypad buttons to in-game functions. Clumsy and error-prone, but unique in itself.