Because this one is very practical and has a really good chance to make it to market. One can build very esoteric structures in a lab environment - which is of

Because this one is very practical and has a really good chance to make it to market. One can build very esoteric structures in a lab environment - which is of course also an achievement - but they are not easily mass produced (too expensive, too unstable, too difficult to manufacture at scale, too unpredictable, etc.).