Urano Grey was the free colour on the mk7 Golf for a period of time. With some of their car models, VW seem to use an unpopular colour as the free colour - presumably a deliberate tactic to get prospective buyers to pay extra for one of the extra cost optional colours.
As far as Urano Grey is concerned, IMO it doesn’t look good on run of the mill non performance Golfs, but I think it works quite well on the GTI ED40 with the contrasting red GTI accents in the same way that Pure Grey works well on the mk7.5 GTI TCR. I don’t know if I’ve ever seen a Urano Grey mk7 GTI in the metal - so maybe it wasn’t a popular colour choice with GTI ED40 buyers? From a maintenance point of view, with Urano Grey being a dark-ish colour, it probably shows swirl marks quite easily, so using a safe wash technique would be necessary to minimise the risk of swirling, and avoiding the many Eastern European hand car wash places and VW dealer service washes would be a must for me.