France test-fires long-range ballistic missile in bid to boost nuclear deterrence

What is that any good for? I mean they have all 100% of their incoming threats within France, right near borders, at airports' arrivals and train stations' platforms, and of course the already bigger part of existing threats in all suburbs of their bigger cities. Nuclear missiles are surely the very last 'idea' that someone would come up with when trying to solve the massive problems they are facing there now or in future.