For some of the ones I've tried (though certainly not all), I'd have thought it really was a case of price justification. I had difficulty telling some of them apart from what one could get ever so much more cheaply at a pot pouri shop (but the pot pouri was longer lasting).
With the exception of the male Creeds and some of the LVs, I haven't been too enthused about the artisanal ones - particularly with respect to staying power.
P.S. It's a bit like debating the merits of paper bags vs plastic bags for shopping. I'll take plastic every time.