Probably, although it seems like directly cultivating them, so they can produce rain in specific areas that would be pretty practical. Actually, it turns out that some ski resorts are using dried bacteria to produce more snow for their ski slopes. Further, once meteorologists figure out how to do it, the bacteria could be used for everything that silver iodide is used for now: Cloud seeding to turn hailstorms into rain, possibly reduce hurricanes (by making it rain sooner, so the clouds don't build up so high), prevent floods and water deserts by balancing the locations in which it rains. The question is whether they're willing to do the work to figure out how, or just keep doing the easy thing of using silver iodide. Did you read my article on cloud seeding, perchance?