The Patek Phillipe that the article opens with yes, but they go on later to talk about the /computus/ which is a purely mechanical Easter calculation accurate w/o modification to year 10,000 AD.
I think it's more advertising for Patek in general. The handful of people who have both the means and desire to purchase such an object likely got informed by their personal networks long ago. But Patek wants to sell $20k Calatravas to merely affluent people who want "the best watch" and this piece helps position the brand. I'd not be surprised if there was significant PR effort from Patek behind the scenes on this one.
For something that's expected to sell for over $10m, I doubt they figured one internet article would surely help sell it. I'm fairly confident anyone who seriously wants to buy one of these already knows it's up for auction.
Well not entirely, it doesn't take into account sidereal adjustments due to tidal shifts or the perturbations of the three body problem (the other planets / moons in the Solar system). But outside of those issues it is accurate to 10,000 years.
https://www.hodinkee.com/articles/the-vacheron-constantin-re...
That will surely sate your lust for mechanical audacity.