What I believe they're supposed to do is connect with an emplacement and you can use them to fire upon a location, but when I pair them with the binoculars it doesn't do anything.

yea, i dont understand what the mission id means

bit late but, when you pair an emplacement with a binocular, you can basically tag an area with a mission ID, a mission ID will last for 1 mins and during that 1 mins if you press B to change view, you will get a top-down view of the area

hope this help