They were kind of the “trial run” for integration. They caused a message to be sent to the public that integration was happening and the public would accept it, and if they didn’t accept it the government would quite literally send the military to back up the law and new way of doing things.
After the Little Rock Nine began attending a previously whites-only school, it was made VERY explicitly clear that integration was here to stay and nothing would change that.
Hope this helps.