A gallery director once complained to me about how artists sign up for the gallery's mailing list just to receive the illustrated brochures or catalogs.  I understand the gallery director's complaint.  It is costly to produce and mail out brochures or catalogs.  He made some comment about how the artist couldn't use the images anyway, because of copyright issues.

As an artist who has been guilty of this in the past, the reason artists do this is not to copy the images.  But rather, it is another way of learning from other great artists.  By looking at the images, an artist learns how others handled certain problems.  It is also a means of inspiration.  Though not the same as walking through a physical gallery or museum, catalogs and brochures provide similar - but scaled down - benefits. 
 
These days it seems that fewer galleries are producing these in favor of on-line porfolios.  The best galleries still see the value of a tangible catalog or brochure.  Whether for an artist or collector, having something which can physically be handled and thumbed through at the viewers convenience is extremely valuable.  It can be returned to time and again. 

True, many will discard it after viewing it once.  Some share them with friends.  Others, like myself, put them in a binder so I can stroll through a "gallery" from time to time in the comfort of my own home; searching for inspiration; always being uplifted.  (I even put magazine clippings into these binders, so I don't have to keep the entire magazine.)