When I first got Poser (6), one of the things which puzzled me was why there were material-modification files in the pose folder, when there was a specific material library section and workspace.  Having learned a bit of Poser history since, I now understand that the MAT pose was a clever hack invented during an era when Poser didn't have the mc6.  But to me, the time when a MAT pose was needed is past.  [McCoy voice]"He's dead, Jim!"[/McCoy voice]
  I consider the mt5 and mc6 to be the weapons of choice for applying materials.  Certainly the library organization would be more logical and easier to learn for the newbie.

Poser 12, in feet.  

OSes:  Win7Prox64, Win7Ultx64

Silo Pro 2.5.6 64bit, Vue Infinite 2014.7, Genetica 4.0 Studio, UV Mapper Pro, UV Layout Pro, PhotoImpact X3, GIF Animator 5