This flower is meant to attract carrion-eating insects, it even simulates the smell of a rotting carcass, so I assume this is what its color is supposed to resemble.
The darkest flowers I see around here are in spider orchids (corybas) https://www.inaturalist.org/observations?place_id=any&taxon_id=140753&view=species
Within species there seems to be a pretty crazy amount of variety in the colour. Some I have seen which seem to have some really dark flowers (But also some really not). Although the darkness may be a really dark purplely-red.
Fungus gnats seem to be one of the more common pollinators of corybas (willing to be challenged on that), and UV seems like it plays a role. So colour we see might not be as important.
I am glad for people who can ID those, they quite confuse me.
A discovery that amazed me at the time, though once made, it only stood to reason. I was growing black beans. While shelling them, I was working in bright sunlight, and I saw that the “black” beans were a very dark purple in that light. So the black color of black beans is actually generated by anthocyanin, just like the color of purple, blue, and pink flowers.
In contrast, when I had a black cat, I noticed that he looked brown while sunbathing. His black color was generated by melanin.
In ultraviolet your black flower might stand out like a light house.
That you see it as black doesn’t matter - you’re not a pollinator.
That it has black pigment might have no cost to the plant, so might not matter.