Wikidata Key Help

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?

• key:brand
• key:brand:wikidata
• key:wikidata