The difference matters in terms of predicting future behavior. If someone loves me, I can safely predict that they won't betray me and will treat my well being

The difference matters in terms of predicting future behavior. If someone loves me, I can safely predict that they won't betray me and will treat my well being as a priority. If they are merely faking it, they might throw me to the wolves (steal from me, kill me, use me, scapegoat me, etc.) whenever it becomes expedient.