Its nice to think your car might eventually appear at historic classic car rallies, but only you know if you will get pleasure from keeping it in pristine condition. And most older cars ,even rust free examples, end up in the crusher.
What you say is spot on and I agree completely. The thing is: I like to keep my cars for a long time and this is the main point. I sold my old Civic from 2010 in September, one of the reasons I sold it was that it was starting to look very rusted underneath and the paint work looked drab and depressing - the truth is I didnt like the car anymore and wasn't a city car where I drive the most... I want to keep this Jazz for 16+ years old so the rust treatment is just a prevention to delay the inevitable so I manage to keep it looking fine or ok for longer and not just 16 years. I plan a different maintenance routine to achieve this: washing more often in winter and applying anti rust treatament.