Even less so in the US with its weird categories that confuse the rest of us: I have never figured out how people with lighter skin then me (mixed white and south Asian) can be "black" or whether Spanish people are "hispanic".
Racial categories are very, very easy to back out from genetics. They correspond almost perfectly: https://www.sciencedirect.com/science/article/pii/S000292970...
"Genetic cluster analysis of the microsatellite markers produced four major clusters, which showed near-perfect correspondence with the four self-reported race/ethnicity categories. Of 3,636 subjects of varying race/ethnicity, only 5 (0.14%) showed genetic cluster membership different from their self-identified race/ethnicity."
That's not to say there aren't better systems. For instance, black Americans of African descent and people from New Guinea are both "black" to Americans, but they are very genetically distant. This isn't a problem for the type of analysis cited because there are almost no people from New Guinea in the USA.
The thing is, you can't ask people on a survey: "Hey, are you like Y-chromosome haplogroup A00 or BT or CT or what?" because people don't know. You can ask them, "What race are you?"
The concept of "race" captures a very large amount of information.
The USA holds to the one drop theory with African ancestry, i.e. any recent African ancestors at all and you're black.
And the reverse with Native Americans, since you have to be practically full blooded to be considered one by some people.
So "hispanic" does not include people from Hispania!
Then again, I have heard of Americans using the term "Anglo-Saxon" for one white group, which no one in Britain applies to anyone from much less than a millennium ago.
In Australia they use Anglo-Celtic, which is slightly better.
Only English people have Anglo-Saxon ancestor (but other ancestry too), so what that really means in English ancestry/ethnically English. Americans will say they are Scottish or Irish or whatever, so why not just say they are (ethnically) English?