Many people use wrist watches for social signaling, same reason they drive expensive cars.
For me personally, it's just pragmatic. I want to know what time it is, and glancing at my wrist is quicker and easier than getting out my phone, and my phone sometimes can't tell me what time it is because its battery died, and I can't bring my phone with me when swimming, etc. I tried naked wrist a while back, and I just couldn't get used to it; whenever I wanted to know the time, it was a real pain to fish out my phone and turn it on.
For me the ideal wristwatch is: zero maintenance: it just always works, no batteries to charge or replace, and it's waterproof and light and small enough to wear everywhere. So "smart" watches are out of the question, as are quartz where the battery occasionally dies. That leaves mechanical automatics, and some unusual quartz watches like Seiko kinetic or Citizen ecodrive.