Gris Perle is not close to Etain at all IMO. Etain is a medium grey and Gris Perle is very light. I would say if you have Beton or Craie, you probably don't need Gris Perle as they are the same white based colour with different undertones. If you love grey, and don't mind light coloured bags, then I think Gris Perle can have a spot in your collection, with Etain. I am a grey lover, I don't have Etain yet but it is on my wishlist. I do have Gris Asphalte and I think Gris Perle is different enough to justify it in my collection.
So many ladies being offered Gris Perle