For example, they could be used on the optical blinders of space telescopes, to reduce unwanted glare. And Vantablack S-Vis has been used in the optical positioning system of the Kent Ridge 1 satellite.
That said, most of these talk about hypothetical ways in which they might be used in the future. And I can't find any follow-up article discussing the success or otherwise of Vantablack in the Kent Ridge mission.
How much are these carbon nanotube coatings actually used for space applications? How successful have they proven to be "in the field" so far?
(I'm also interested in substances based on etched nickel-phosphorus alloy, such as the earlier "super black", but I don't know if these are different enough to justify a separate question.)