Because it was an act of faith. They entered the promised(!) land. But it did not turn out to be their home. When they noticed that they as believers did not shrink back (Hebrews 10:38–39), they confessed their faith in God, believing that they would see the fulfillment of his promises in the future in a better country, that is, a heavenly one (Hebrews 11:14–16).
13 These all died in faith, not having received the things promised, but having seen them and greeted them from afar, and having acknowledged that they were strangers and exiles on the earth.