Why did Emperor Charles V initially recognize the Schmalkaldic League in practice?

Emperor Charles V initially granted the Schmalkaldic League de facto recognition primarily out of fear that the alliance would join forces with his primary rival, Francis I of France.1

Throughout his reign, Charles V was preoccupied with significant foreign entanglements, including ongoing conflicts with France and the threat of the Ottoman Empire under Süleyman I in the east. Because these external pressures required his full attention and military resources, he was not in a position to suppress the Protestant territories by force immediately following the league's formation in 1531. Consequently, he maintained this stance of recognition until 1544, when he finally concluded peace with France, allowing him to turn his military focus toward the league and initiate the War of Schmalkald in 1546.21