Area denial is a useful. Someone flying a drone at someone making a speech, a 747, or a football stadium then getting it to land in a parking lot is fine.
Anyway, you can build mortar's for under 100$. Rockets are a flexible terms, but 10 for under 20,000 is very possible. Importantly your drone needs to carry the box and what blows up where a rocket can be the box that blows up messing with your payload calculation.
PS: "Rockets red glare" refers to a mechanically simple devices that are still useful weapons.
Anyway, you can build mortar's for under 100$. Rockets are a flexible terms, but 10 for under 20,000 is very possible. Importantly your drone needs to carry the box and what blows up where a rocket can be the box that blows up messing with your payload calculation.
PS: "Rockets red glare" refers to a mechanically simple devices that are still useful weapons.