Raster Reference Origin. Why is it where it is?

OK this has bother me for quite awhile so I need to ask.

If you attach a raster reference the default location places with the upper left corner of the image at 0,0.

If you attach interactive it uses 2 opposite corners via data points.

The question is why is the origin of the file the UPPER left corner of the the BOTTOM left pixel?  Why not at the corner of the image?