On multilingual Wikis [[ https://www.mediawiki.org/wiki/Extension:Wikibase_Client/Lua#mw.wikibase.label | `mw.wikibase.label` ]] and similar functionality (`{{#statements:…}}`, …) will show the label in the user's language, if possible. Due to this different label usages (`L.lang`) will be registered for a page depending on who visited it since it was last touched (see https://github.com/wikimedia/mediawiki-extensions-Wikibase/blob/master/docs/usagetracking.wiki for details about why this is).
All labels are potentially relevant (as they can be used depending on the user's language) for the page and changes to any single one of these can affect the rendering of the page for certain users.
Due to this, I suggest to track **all** labels as used in this case:
This will make the entity usages for a page more stable and not depend on who has visited a page since it was last touched (as much).
For performance reasons and completeness, we might want to track such a thing as `L.*`.