Are whiteness and blackness useful concepts in the study of popular music?

The Blackness and whiteness concept may have been useful when describing the history of music, however it is no longer relevant to music today. David Hatch argues that 'popular music has always depended on interactions towards white and black traditions', today most of popular music has a mash up of different genres and cultures. The stereotypical genre's we associate with 'white' music, such as rock and roll was originally considered to be 'black' music, however radio stations in the 1950's would only play the white version. Does this mean that rock and roll is white? Same as stereotypical 'black' genres such as rap, Eminem has been a very successful white rapper so do we still define this music as 'black'? 


I believe that there are several other factors that need to be considered when defining music, and cannot be simply defined as 'white' and 'black'.