Wikidata properties are practically by definition qualifiers. Consider time for instance, there is the "point in time", the "start date", the "end date" and all of them are in relation to something else. For instance when a Noble prize was awarded, when a King ascended to a throne and when for whatever reason he was no longer the ruler ... "Le roi est mort. Vive le roi !!".
Working on Wikidata items is very much a learning process. As you go, you learn and come to conclusions. For me it is now obvious; properties about time and dates are qualifiers.. always.