I never owned a NES, but had a SNES and my brother also borrowed his friend’s Mega Drive (Genesis for those of you in the US) from time-to-time. All of us would blow the connectors on the cartridges, regardless of console. If anything went wrong with a game, the first step to troubleshoot was to take the cartridge out and give it a good blow.
It was never about how the console actually worked, a five year-old isn’t going to logically think about that. It was all about a perceived performance increase by doing it.
I’m playing through New Vegas right now. I have one of the back buttons assigned to quicksave. I also changed the default camera button to one of the back buttons, because I don’t use it often enough to warrant it being on the bumpers. And I have just assigned one to toggle collision, because sometimes you need that when playing something built in the Gamebryo engine.