As a left-handed person (or corrie-fisted) as we are known in Scotland I certainly did research this feature of the Apple watch. However, it was not really important as I have numerous analogue watches all of which I wear on my left wrist out of necessity to reach the winding/adjusting crown. Though, I do occasionally wear some of my self-winding models on my right wrist just to see if anyone notices!
I suppose I'm slightly unusual as I only write with my left hand. My right hand is dominant for all other activities. (Golf, cricket, throwing, hammering nails etc.)
As a complete non-sequiter, in my first year in secondary school, 8 of my fellow pupils in a class of 14 were all left handed. Possibly because we were all old enough to be beyond the period when parents thought it necessary to try and 'condition' their children to be right-handed.