Because everyone else was doing video game physics, so why not?
First off, let's address something. What does Super Mario World for the Super Nintendo have to do with quantum/theoretical physics? Not much, right?
Well, I stumbled across an article on mentalfloss.com, which I'd recommend looking at if you're at all interested. http://mentalfloss.com/article/17994/super-mario-world-quantum-physics-lots-fun
It describes how some anonymous gamer (with a lot of time on his/her hands) programmed a playthrough of a Mario level where all previous attempts were superimposed upon each other. This level is gruelingly difficult, so the player dies a lot, but eventually one of the Marios survives the level, one out of...a lot. Here's the clip.
So, it's just a bunch of Marios who die, and one of them survives at the end. What does this have to do with theoretical physics? Let me just define some stuff briefly, and I'll get to the point soon enough.
The Schrodinger's cat paradox is a theoretical experiment where a cat is locked in a sealed box with a radioactive source, a cat, and some poison. If a monitor in the box detects radioactivity, the bottle of poison breaks, and the cat dies.
But, a certain interpretation of quantum mechanics (named the Copenhagen interpretation) would state that in this scenario, the cat could be simultaneously dead AND alive. But obviously, if you looked into the box, you wouldn't see some zombie-cat-hybrid thing; you'd see a cat that was either alive or dead. This moment demonstrates the point where quantum superposition (scenarios "stacked" on top of each other) collapses, and one of two courses of reality takes place. Either the cat's alive, or it's dead. It can't be both.
BUT WAIT...THERE'S MORE
The many-worlds interpretation of quantum mechanics says, yeah...the cat is alive. It's also dead. But it's alive in one universe, and dead in another, and these two universes have nothing to do with each other.
So is it true, then, that there can exist infinite universes, one for each possible scenario of every decision or event ever? That's where Mario comes into play. The death of all those Marios represent a bunch of universes where he failed to complete the level. But, if there can be universes for every scenario, he has to survive at least one...right?
Well yeah, he does! That universe, where he survives, is represented by the final Mario left at the level's end. The programmer stated that this entire program demonstrates the MWI (many-worlds interpretation). And it does, to some extent, even though obviously not every possible outcome of Mario was shown here. But it's enough to prove a point.
So the next time you get really ticked off when you die in a video game, just remember...somewhere, there's a universe where you succeeded.