Patek and Rolex have generally always held value well. The internet has brought price transparency and created a secondary market that has made this true for most well-known brands these days, with the caveat that there is not a high degree of liquidity (yes you can sell a Rolex same-day at a pawn shop but you'll take a big hit, otherwise you are waiting a while for a buyer and navigating various risks like scammers).
So you likely won't get rich day-trading (or even collecting) watches, but besides the initial capital investment it is not as irrational as it seems at first.
Of course, that only adds to the signaling power for the classes where merely having money isn't enough, and being a "savvy investor" is a status marker (ie. the upper-middle and nouveau riche).
The Patek Nautilus PG mentions is particularly interesting as a status symbol as it has not only held value but, for various reasons, been an outlier that has appreciated drastically in value. It'd be gauche even on Sand Hill Rd to wear a hat that says "My investments beat the S&P 500" — but for the last few years, flashing a Nautilus (~413% investment return from 2016-2026 vs ~322% in the S&P) is the equivalent of that, a self-reinforcing cycle boosting its value as a Veblen good where the high price is the point.