I can see this as an issue if it was a first person game, but for this case, I don't think it should matter. Honestly, if they switched all characters to left handed, most people probably wouldn't even notice.

In any case, just because you can summarize an action into one word (i.e. mirror), doesn't make it that much easier. It's like saying "you could climb, rappel, hike, and camp up Mount Everest... but it would be much easier if you just walk up it"
Correct me if I'm wrong but there is probably no <sprite class="mirrored" style="orientation:EverythingIsOpposite; coding:easy;">...

But, yeah, if it makes people comfortable and it doesn't end up hurting the game in some unforseen way, why not?