I imagine a drone hunter flight of multiple drones, multiple drones implies multiple receivers, multilaterating the transmissions of the target, and splash.
Only works on surveillence drones that need to be transmitting, and don't emit only in the direction of the intended receiver.
Based on what we're seeing in footage and interviews from Ukraine it absolutely matters. Hearing a drone is often the warning that you're about to get shelled.
People really fixate on this swarming concept like that murderbots video and breeze right past the more high impact basics.
Good point that a vertical wing is hard to see from below, but quad copters don't have wings, and so don't have that problem (the rest of the body has width, and is visible, but that's mostly the same with a tailsitter).
They are already impossible to spot as it is at certain heights.
It would have to be right above them though.