A country will not send a costly missile if the desired result is not going to happen.
Similarly, God will not send a team to accomplish practically nothing while the same team can accomplish immense results if they were sent later at right time to right people!
What was best for God—sending the army of angel at the time of Jesus’ birth to some shepherds—which brought no gain, or to send the same team at the time of Jesus’s trial, to Rulers or Jurists who can bring about much gain in favor of God’s purpose?
The very fact that army of angels were sent once means they can be sent again for a worthwhile cause. If they are not sent for the right cause and at right time and to right people means they have not been sent at wrong time at wrong place and to wrong people.
God will not perform wasteful acts—hence army of angels coming to shepherds makes no sense, serves no purpose!