This tech is not really new - in Germany, Austria and Switzerland, "cloud seeding" airplanes have been flying for years (to avoid hailstorms rather than to make it rain), although the efficacy of the method is disputed, so it's not really widespread. I only learned that this is done where I live when I saw a small airplane flying dangerously close to an approaching storm (which GA aircraft usually do their best to avoid) and then read an article about how they miscalculated the strength/direction of the storm and barely managed to avoid it.

Wikipedia article (only available in German): https://de.wikipedia.org/wiki/Hagelabwehr#Einsatz_in_Deutsch...

Article about the history of anti-hail airplanes in the Rosenheim region: https://www.hagelabwehr-rosenheim.de/geschichtliches.php