Real "2 gun mojo" is very rare, but it does exist in some people.
Most of us can't throw a 90mph+ fastball, or deadlift 500lbs. There are people who can.
Some people are natural shots. They "use the force" (or whatever you want to call it) and can make astounding shots point shooting and do even better using the sights.
Others have a degree of talent, and hone it with practice, sometimes decades of practice.
I suppose there might be someone who actually could aim both at the same time, but I think advanced point shooting skill is what is displayed.
Shooting two guns ALTERNATELY, on the other hand is a fun game, and allows even regular mortals the opportunity to aim them.
The cowboy hero (and the Lone Ranger!
) might use 2 guns, and considering the real fact that two guns doubles your firepower before a reload, and MIGHT just have happened once or twice in real life shooting SA revolvers back in the day, makes it cool.
The modern action hero/heroine wielding a pair of hi cap autos, aiming in opposite directions, clearing a room of bad guys surrounding them, and as a dramatic finale, crossing arms and shooting the last pair on opposite sides is a movie pipe dream.
But it is entertaining to watch!