In some respects -- the unique carbon-fiber reinforced plastic (CFRP) body module -- it was a learning venture, though I would say the original Mini E and ActiveE were more transparently engineering exercises involving actual customers. The i3, available for sale instead of strictly through lease, is meant to be a consumer product, just as every other BMW model.
That said, I don't know what sort of sales expectations BMW had off the top of my head, but I imagine they were higher than what it is seeing today.