To paraphrase John Heskett, writing in Toothpicks and Logos, a designer is merely someone who takes account of his skills and applies them to imagining and realizing objects and contexts that didn't exist before.
A corollary of this line of thought might be that a designer is defined by means, rather than ends - by methods rather than products. There is art which is indubitably art, and design which unquestionably design, but in between there is a realm of grey: objects which are both art-like and design-like. And I, for one, don't think that this ambiguity is problematic.
Art, or objects displayed in an art-like manner, is interesting, because it is an ephemeral experience; in this case, I wonder how the "white cube" would benefit from a more traditional "product." Christian has identified the ability of art to provoke conversation and thought - contexts that didn't exist before - in a way that consumable artifacts might fall short.
There is something to be said for insular design (cf Boym partners) - it may not make it directly into the consumers' hands, but it provokes other creative types to think in new ways... Partition's message could have a viral impact.

