[homebrewer]

It's about as reliable as "investing" in cryptocurrency. The prices on luxury watches can come crashing down at any moment, especially if there's any sort of economic shock.

As a side note, my cheap, but very well calibrated, mechanical Seiko keeps time as well as a couple of cheap quartz (100% original) Casios I have. It's running at 13 seconds of error accumulated over the last 125 days (almost to the hour), which gives 104 ms of drift per day. The two Casios have ~85 ms and ~120 ms of error per day.

So you're not even paying for insane accuracy or anything like that — thanks to modern engineering, it is available in a mechanical that costs tiny fractions of a Rolex.