The facial graphic is effective iconography because it:
SHOWS BOTH ARTISTS: This is effective as their faces will become instantly recogniseable
CONTAINS FACIAL DOTS: This is a style navigation point to fans but also another iconic look, individual to NTLS to make them instantaneously recogniseable
EQUALLY SHOWS BOTH ARTISTS: Richard Dyers star theory discusses how artists can be enforcers of certain ideaology. The equal showcase of both artists shows NTLS think that no memember of the duo is notmore important for their race or gender and so equally display both of them.
IT'S SYMBOLIC OF THEIR DEBUT VIDEO: in the performance section of the video you see Lulu and Nathan together and individually a lot, showing how they are a team. This merged facial graphic also shows just that.