I am considering giving up my own mating and framing.....
Alberto,
I consider matting and framing to be the final stages of the over all process toward producing a fine print. I wouldn't even consider offering one of my photographs for sale without it being mounted and matted. I've considered not framing them. But I'd hate to think of the ghastly things people might use. Even after money has been exchanged and the photograph walks away in someone else's hand, it's still my photograph and I care how it is finally presented. Putting it in the kind of frame I prefer and selling it that way makes it just a little less likely it be put in some other type of frame latter. I won't even think about what other colors of mat people might consider.
To put it succinctly, I consider matting and framing to be part of the image, not an add on. I wouldn't think of giving it up.
Peace! Sidney