Of course it makes a difference whether you’re pretending or doing for real, but what I’m saying is that pretending is already half of the battle.
Boxers don’t just spar in the ring all day, they practice shadow boxing to get their moves right. Other martial arts have katas or training forms for the same purpose. Those are all forms of pretend fighting, with the purpose of training correct body mechanics.
I would assume for instance, that when you’re stage fighting, you probably still throw your whole body into a punch so that it looks like it would hurt even though it doesn’t connect. If you’re just flailing your arms like a grade schooler on his first day at the playground, you’re just not going to convince anybody.
And if you can pull of a convincing haymaker and purposefully not hit the other guy’s face, you’re literally six inches away from doing so, which is miles ahead of anyone who hasn’t practiced at all. All you gotta do is adjust your aim a little, and not immediately give up if you do get hit back. But with a guy the size of Mamoa I’m not too worried about the latter.