No, but most lefties don't have the dexterity to control it with their right hand. Think about it as a righty if you had to do a lot of pinpoint control things with your left. I have never worn a watch on my left wrist. Unless they make a lefty version or it can be worn upside down and have the screen flipped or something they will lose a lot of sales.
Being a leftie I have to disagree here.
Most true lefties are ambidextrous . I am.
I bat right handed.
I play the guitar right handed.
I write left handed.
I eat left handed.
The last time I wore a watch was in 1973 .It was a Rolex.
I wore the watch on my left wrist and used my right hand to make adjustments on it. No problems whatsoever. It was stolen and from that point on I swore off watches.
Oh and.
I might be going back to wearing a watch. A 2015 version of a watch.
An Apple Watch.