Comment by rm999

I actually see that as an argument against using j. The meanings of a unit vector in real space and a dimensional unit in imaginary space are different concepts even if it's common to represent both in 2-dimensions plots. It seems to me that this would only cause confusion/ambiguity. When I look at a plot I want to know what it's representing as soon as possible, and the way the axes are labeled is part of what helps me.