Just compelled to chime in : ) I do everything righty. There is nothing that I do that is as a lefty would...except musical things. I play all stringed instruments lefty, and have been playing for 50 years and as a professional musician on guitars and basses for most of my adult life. I have some theories about left/right handedness as it applies to music, and I think it's a mistake to assume that our stronger hand or more coordinated one is the one that dictates which way we are naturally born to play (as opposed to which way we decide to play, which I think is fine too). There are many great drummers who play lefty and reverse their kit, but there are also many who play true lefty (with the right hand hitting the snare and the left riding on the cymbals and hi hat) who don't change the righty drum positions. When I sit at a drum kit the backbeat, the snare, is definitely rooted in my right hand. Since no one wants you to mess with the drum setup : ) I have gotten used to being more or less righty in my feet, since the right foot is on the kick drum pedal with a "normal" righty kit, but that's ok with me because my right foot is for sure my more coordinated and stronger foot, Always kicked righty growing up in soccer. It's not where my downbeat is naturally but I've learned to fudge that a bit when I get a chance to sit on a drum kit. But my left hand is doing the steady cymbals and right is doing the snare, as a natural (musical) lefty. When I used to give lessons there was always the question parents had about the lefty child and should they play lefty? What I would do is have them play a simple drum beat on the table, just a simple boom-chack- boom boom- chack thing. And nearly always, with both right and left handed kids, the "boom", the downbeat bass drum, would be be with their right hand and the "chack", or backbeats/snares would be with their left hand. Only maybe two times out of all the times I did this were the kids not natural "righty" musically, as in to which hands functions and roles fell.
Strumming/picking or fingering with a certain hand doesn't necessarily line up with what one's natural music side is. It's a different thing, a different internal guide than the one that determines which hand we are inclined to for writing or throwing or which foot for kicking. I don't have any real scientific proof of any of this : ) it's just from my observations of being a total righty in one world and a total lefty in another, and I find it very interesting. One funny thing is that many of my friends are people who I know through playing music together, and they identify me as a lefty person, which I don't at all. And when they see me doing something, then maybe everything else righty they think it's very strange. But I don't. It's just the way it is : )