The Role of the Artist Assistant

What do we think of the role of the artist assistant?

"But what's most striking about the artist-assistant relationship is how it is airbrushed from public consciousness. Behind every great artist might well be a highly skilled team of assistants, but that truth is suppressed for fear of shattering our illusions: the lone-genius myth helps sales, and is partly what gives an artwork its mystique." - Stuart Jeffries,The Guardian, Friday 22 March 2013

If you decide to buy art, do you care that the artist hired people to do the actual work? If this holds for a painter or a sculptor, does it hold for a writer? Or a photographer? What are the limits and when does it affect the value of the work? Will knowing the actual working 'craft' person make some items more valuable in the future? Can 'craft' people be used by artists in art fairs or in competitions? If Hirst or Hockney or Emin use assistants to do the actual work, at what level of professional development can an 'artist' hire help to step in and make the work? My understanding is that a "Rembrandt" done by an assistant, or mostly by one is worth much less today that for a painting done by the Master. Does that still hold true? If so, will it continue to hold true. 

Comments welcome.