Here's a new drone (warning, acronym creep) called the CICADA, or Close-In Covert Autonomous Disposable Aircraft.
It's tiny and weighs only 65 grams. Essentially, it is released in a swarm (dozens at a time) by an aircraft. Once released. each drone flies/glides to its target, landing within 5 m of its target location.
What are they good for? Rapidly deploying geographically dispersed networks of sensors and/or mesh communication nodes.
Why use them? They have the potential to provide P2P communications and real time intel to human units and autonomous weapons operating in a contested environment.
Longer term? They are one component of vast networks of drone sensor/comms nodes could provide over the horizon services that surpass those provided by satellites and traditional approaches.