The description makes it sound like if you are firing weak hand (or strong hand) you might be outside the range of the watch? They say "just a few inches" which implies less than a foot. That's not going to work for law enforcement or anyone really. Honestly sounds like they didn't think too hard about real world usage. That describes most handgun manufacturers though and isn't strictly limited to smart gun manufactu…
The intention clearly seems to be for the watch to be worn on the same arm that you hold the gun with.
People practice one handed reloads and failure drills.
Even in competition you are regularly required to alternate no strong hand only and weak hand only so it isn't possible to put the watch on the right hand. Proper technique also has you anchoring the unused arm.