[petsos]

It may not be important by itself, but it is important to be right. Her nationality may also not be relevant but if someone writes that she is Chinese and she is actually Russian (example), it is important that it gets corrected.

[tesseract]

Fortunately this is not a common scenario, because the nature of the English language doesn't make it easy to inadvertently imply that someone is Chinese, Russian, or indeed any nationality at all.

(I am aware that singular 'they' is grammatical. Doesn't stop it from sounding really awkward when the referent is a specific individual.)

[fedd]

is she Russian? :)