Well, their entire business model depends on persuading their clients that natural diamonds are a rarity and better than human-created ones.
So I don't really expect them to offer a non biased view here, even though their audacity is astounding.
In this case the market needs the average consumer to buy into that status symbol, and enough of them are price conscious that a cheaper alternative that almost nobody can tell is cheaper is quite a draw.
(I believe I've only seen them in hotels)
First time I saw them I thought it was some kind of dystopian joke.