I have historically mapped the keys “wikidata=” and “name=” of restaurants such as McDonalds. According to the OSM wiki name vs brand is the contributor’s pick in this instance.
However, I have just learned about “brand:wikidata=”. Is there a useful difference to use this key with the keys I normally use or would it be redundant?
There may be a difference between the name and the brand, e.g. if the place name or owner is added to the name. Since this is not the case with the fast food chain mentioned, there is actually no reason to duplicate it. However, the Wikidata value does not refer to one branch but to all branches, so brand:wikidata would be more correct.
Like you said, wikidata refers to all branches. So why would it be more or less accurate to use “wikidata” or “brand:wikidata”? Wouldn’t they both be just as accurate?
As always, there is no clear-cut black or white. At McDonald’s, however, I would definitely be at name=McDonald’s brand=McDonald’s brand:wikidata=Q…