my reason for left-side carry sometimes, is due to nerve damage/tendon issues with my "strong" right hand. There are times when it flares up enough that it becomes difficult to operate the pistol properly with my right hand. I usually know 1st thing I wake in the morning if that hand is going to be functional that day- so on those days, I'd carry left-side.
I do this with pocket pistols already in CCW.
But, I've always made it a habit to practice shooting either hand- in case of something like this, or injury to/loss of use of, the strong hand. I alternate when practicing- 1 mag right hand, next mag left hand, etc. That practice has long since paid off.