Risa can be effective against flying things provided she's given 200 m² of free space on the ground to set up a Surface to Air missile battery...

Marza: "Why exactly are you even using 1960's equipment?"
Risa: "Bcuz'... This the only SAM I bothered to take a good look at in that museum in Belarus"
Marza: "So you're using a magically empowered museum piece?"
Risa: "Yes... Now stop talking..."
Marza: "It's flown behind a building..."
Risa: "...Shit..."

Yeah... Not exactly useful in a city...