@mathmax Instead of answering your question, I would like to broaden it with respect to the usefulness of meta keywords.
I am by no means a SEO expert, so correct me if I’m wrong…
From what I’ve read/learned on the topic of SEO: Keywords are dead, long live the keywords.
Keywords as a meta tag are no longer used by Google (and probably others) for a long time. Since 2009 I believe…
But using the right keywords in other parts of the page is however very important. And ‘right keywords’ means keywords that very well describe the content of a page and are used by users in their search query.
These other parts that are more important and indicative for the content of a page and hence have more impact on SEO when containing the right keyword, are:
- Url
- Title tag
- Meta description
- Page content
- Header and subheaders
- Image alt text
- Internal linking
- Domain name
Hope this helps…