But my point is that it isn't useless, but it just isn't useful in the way you describe.
Gunners use it for a split second to get the initial notch to aim at. That's it, you don't need it after that.
No need to have it active while you're shooting, no need for a pilot to take it. An engie can take this for a quick spot instead if the gunner calls for it and you already have 2 spyglasses.
Its the exact same kind of use as a spyglass - you use it once then forget about it. You use it again when you lose a spot - just like you use the rangefinder again when reengaging after going through a cloud or a new spawn.
The only change needed imo is to remove the useless dotted circle.