While specific contributions by Garibald II are unknown, Bavaria during this period was experiencing gradual Christianization; this process was aided by ties to the Lombards, who were transitioning from Arianism to Catholicism.
Garibald II's lineage ties him to the influential Agilolfing dynasty, which dominated Bavarian leadership for centuries; and his marriage to Geila—as she was the daughter of Gisulf II—connected him to the Lombard duchy of Friuli.
Such dynastic alliances were a major tool for securing peace and cooperation between neighboring polities (in this case, Bavarian and Lombard territories) in medieval Europe.
Garibald II's reign occurred during a formative period for Bavaria, as the region transitioned from tribal leadership to a structured duchy under the Agilolfings.
Although, as noted, few details of his reign survive, Garibald II is a significant link in the history of the Agilolfing dynasty, which would remain influential until the 8th century.