The idea behind midi and the reason for its success was that it would be a universal standard and allow any device to speak to another thus allowing keyboards and modules form companies who would otherwise be in direct competition to each other.
No longer did everything have to played live but could instead be sequenced and played back. Early home computers such as Atari and Commodore supported MIDI and very soon were not only used in huge recording studios but also gave rise to the now common home studio setup.
