One can debate if it's WoW that should depict computer games. Personally I would have chosen Pong oder PacMan, probably Pong.
But computer gaming has redefined the world, for better or worse.
MP3 did change the world cause it was first. Just like the cars 100 years ago changed the world, even when a horse and buggy was waayyy more practical and faster and cheaper then. Mrs. Benz' car was simply shit when she made her historical drive to relatives, but the concept of cars changed the world. Same with MP3s. AAC is irrelevant: one in a long string of different forgettable formats. MP3 was the first psychoacoustic format unlike mp2, where you leave out stuff that doesn't matter subjectively, same as with all our video codecs. The only competitor there is JPEG, which IIRC was before MP3, another lossy format. Only that crucial innovation allows us to have digital media across a network, medialibraries in our pockets, etc.
Tho there should have been a few other inventions, more important than all the consumer facing things. Like COBOL, like spreadsheets. Stuff that changed society behind the curtain but changed it nevertheless. But it's easier to bring in people and especially kids going to the museum (schoolchildren who have to go to a educational day trip) with consumer and especially kid facing technologies. They can relate to WoW, better than to Pong, and COBOL ist totally alien to every one of them and therefore booooring.