Greenland was granted autonomy from Denmark primarily to give the people of Greenland more control over their own affairs and better manage their local resources and culture. Before gaining autonomy, Greenland was governed directly by Denmark, which meant that many decisions were made far away, in Copenhagen.
The desire for self-rule began to grow after World War II, as many places around the world were seeking greater independence and autonomy. In 1979, Greenland was granted Home Rule, which allowed them to have their own government and make decisions on a variety of local issues, like education and health services. This was a big step towards self-governance.
In 2009, further steps toward autonomy were taken with the Self-Government Act. This act gave Greenland even more power, including control over natural resources and the ability to negotiate international agreements. The people of Greenland wanted to preserve their unique culture and improve their economy, and autonomy was seen as a way to achieve those goals while still maintaining a connection to Denmark for defense and foreign affairs.
Overall, the move towards autonomy was about wanting to have a greater say in how their own lives and resources were managed.