Ukraine for example, prepared itself despite forecasts of low probability of an attack. Israel's military intelligence on the other hand knew the details of Hamas attack to the point and chose to ignore it despite high probability of the event.
I know the US government has depended on forecasting in intelligence and defense for a long time built on the RAND legacy. I find it hard to believe most other sophisticated nations don’t also do similar forecasting and planning around forecasts given how influential these efforts in the US are.
As a forecaster: It's fun! It's an interesting way to learn about the world -- rather than gathering inert facts, you're forced to integrate them into a mental model, and then your model is tested for its validity empirically. It's also difficult and competitive, if you like that sort of thing.
As a consumer of forecasts: There's good research that prediction markets and other forecast aggregators are the best technology we have as a society for quantifying uncertainty. Not everyone will listen to them, just like not everyone eats their veggies, but c'est la vie.
I don't think there's too much risk of self-defeating forecasts (where a low forecast lulls decision makers into a false sense of security) - at least not yet. They're still pretty niche.
I know pretty surely that for example people in respective areas of finance are pretty interested in forecasts and will often act on them.