Oops! I didn't see this before I created another thread about this feature.
It is a really nice addition. It enhances the relief of an ortho that otherwise looks flat.

I first built the texture using the default pixel size (it is also the default size for the ortho).

Building an orthomosaic with Transfer model texture
unchecked finished processing in 107.826 sec
Building an orthomosaic with Transfer model texture
checked Finished processing in 38.987 sec