Essentially when using the binoculars, pings/ marks that you make will display with a different symbol than the standard mark.
Enemies killed within a 10m diameter will give an assist to the player that placed the spotter mark.
It helps make binoculars more useful and gives players more incentive to work together.
Like this!
A marker placed with binoculars should show the distance to that marker. Similarly, scouts (marksmen) should see the distance to the marker in the eyepiece of the scope.
Having the range of a marker would be great, especially for M8 Scott tankers. Somebody could mark a location with a gaggle of enemies, and the M8 could use the range on the marker to make themselves a quasi mortar.