Shooting two guns at the same time does in fact look cool. That's not a myth. Hitting two targets with two guns at the same time is really hard though.
Supressing fire is all about distraction and area denial. You can defintely fire two handguns accurately enough to do that. You might not get all yours shots in the 10 ring but you could deny access from one direction of a street for example.
Years ago when I did my armed securities training, we went to a hillbilly ass shooting range, that was basically just some dudes big ass back yard. Did the double gun thing. Turns out, almost everyone unconsciously aims with their dominant hand and tracks that with their non dominant. Meaning you're basically shooting st the same target with both guns even when you think you're trying to go for both targets.
Some people, however, will just randomly shoot with their non dominant hand, and it's incredibly dangerous how wide those shots go. Like, damn near beside or behind them. Humans, it turns out, are fucking dumb
I can't imagine double aiming like that, maybe slowed down a lot. i could see training alternating fire on a single target being possible with practice.
This one seems the least believable to me, but I admit I have almost no experience shooting guns. Maybe you won't be super accurate, but it would work if you were going for suppressing fire against multiple bad guys while trying to get to cover or something.
I wonder if someone practiced exotropia and multi-focal tracking (or rapid mono-focal switching) if then dual vector shooting could technically be learned.
Regardless if anyone attempts this, please post a video of your face while you do it. For science.