"Early examples of war as metaphor in US political discourse include J. Edgar Hoover's "war on crime" in the 1930s".

We've been using it as a metaphor since 1930's. It hasn't impaired the "real" usage of the word "War" so far. I doubt it will in the future.

George Carlin more than 20 years ago.

https://www.youtube.com/watch?v=ilipDBclxRc

Well, not long after the term started (Hoover), the US Congress ceased to "declare war" when proceeding to engage in what obviously is war. Now it's just "kinetic military action" or some such, never a statement of "the USA hereby declares war on ______ ...".

That ship done sailed. Like, in the 1960s. No worries, though, because if any concept deserves impairing and besmirching, surely war does?