The launch of a new game console is always preceded by an advertising blitz, and the coming of the Nintendo 64 back in 1996 was no exception. One of the more iconic ads of the marketing campaign proudly proclaimed that when the appropriate time came, dinosaurs would fly. Positioning Bowser front and center, Mario is almost a visual footnote as Nintendo's marketing department spelled out just why the new console would break all kinds of new ground. Vintage Computing and Gaming has a scan of the ad in all of its Kooparrific glory.
It seems more likely to me that Nintendo realized a larger number of people would actually be able queue up for a system (or simply just go to the store and buy it) on their day off. Stronger opening day sales numbers were (and still are) important to console makers because they meant not only more press coverage, but also more license for ecstatic gloating and self-aggrandizement from the company’s PR department. If you hadn’t noticed already, hyperbolic show and bluster were dominating themes in 1990s American video game marketing.
It's a shame that Bowser is technically a large turtle and not a dinosaur, and he could only fly in Super Mario 64 provided that Mario spun and tossed him by the tail, but accurate character specifics apparently do not sell game consoles. The "September 30th" slogan was a great line though even if it doesn't rank as memorable as other classics from the genre such as "Genesis does what Nintendon't", "Welcome to the next level", "Play it loud!", and "Now you're playing with power!"