Do I need to localize my app in the AppStore?

Question

Marketing

I have this question:
On duty, I began to study the promotion of mobile applications in the AppStore, many write about the need for localization and ASO, in connection with which I had a question - do I need localization for my applications? We are talking about readers with a built-in store with books in Russian.
What happens if I add several localizations of my applications to iTunes connect, and in all localizations the keywords are in Russian? And should it be done.