When a user deletes or moves a page on Wikipesia, and the page has a wikidata entry, the action modifies the wikidata entry to change or remove the listing for that langage Wikipedia. This result is usually desired, but occasionally it isn't. A user should have the right to not have this wikidata change happen when deleting or moving a page - uasing an extra checkbox which defaults to yes changing wikidata.
Indeed this isn't really wanted. Most people see the option, are afraid to do harm to Wikidata and uncheck it and in doing so cause harm to Wikidata. Not everyone that edits Wikipedia knows about Wikidata and what happens on Wikidata when they do something on Wikipedia. So I would advise against it. In those exception cases it's better to manually adjust Wikidata after all actions on Wikipedia have finished.