When you bring back the Halflings, their gratitude knows no limits. They immediately spread out into all provinces you have completed and populate the "known and secured lands". From then on, Halflings from every completed province will send a small obolus of a new resource, Divine Seeds, to your trader where you can collect it daily. Seeds, like Mana, is a decaying resource. Obviously, the more provinces you complete, the bigger the daily Seeds delivery will be.
Of course, there's also a group of Halflings that wants to stay and settle in your town. Their goal is to celebrate the ultimate harvest festival with you, their savior. Therefore, they build up a giant farm, where all kinds of fruits are cultivated. The date of the harvest festival draws nearer and nearer and there's still so much to plant and grow and harvest... Will your town be ready for the ultimate party in time?