Difference between Intersect and Not Intersect is Nothing

My app uses Worksheet_Change(ByVal, Target as Excel.Range)

To narrow the scope of the event I then use either:

If Not Intersect(Target, Trading) Is Nothing Then

If Intersect(Target, Trading) Then

The large majority of code samples that I've seen for the Change Event all use the first form. Yet intuitively I would expect the 2nd form to be operationally identical since NOT and IS NOTHING appear to cancel each other. And because it eliminates NOT and IS NOTHING, the 2nd form ought to be more efficient. In fact, in my application the 2nd form seems to do the same thing and work just as well. Is there some gotcha or subtle distinction between the two forms that I should be aware of?