I would never wear it, but all that's important (as others have said) is that you like it, can afford it, and it fits with your lifestyle.
But your point about Vegas is wrong. Vegas is my second home (I work in the gaming industry) and everything doesn't have to be loud in Vegas.
Vegas is the land of the poseurs. Anyone who lives and works there knows it, and can readily spot them from a mile away. Fake atitudes, fake clothes, fake jewely, fake watches, fake bags, and overbought fake lifestyles. All trying to make people think they have more money and a better life than they really do. Your post is a prime example. The watch (if genuine) would easily be worth far more than the car. Can't tell you how many times I have seen guys sporting blinged out watches, chains, or clothes (while bragging about how much everything cost) all of the sudden clam up when they get asked to buy a couple of bottles at a club, or when the meal comes to $1,000. Wearing a $30k watch (if genuine) and can't sit at a $100 blackjack table? Consider that being called out ... it happens all the time ...
When in Vegas, I am able to get VIP treatment everywhere I go. Although I certainly don't dress like a bum or wear a Timex, there is no need to be "loud" to get treated well. People figure out I am probably doing well financially because of how I carry myself, and how I actually spend. No flash, no hype necessary. I don't have to advertise or try to sell it.
Even if someone is an athlete, celebrity or rock star it's still really not necessary. Look at LeBron James. Could wear all the iced out stuff anyone could afford and he's normally wearing conservative clothes, and an understated AP (due to his endorcement deal). Yet everyone knows he's the man. He doesn't have to prove himself to anyone. When anyone has to dial up the volume to "prove they belong", they ususally don't, and it readily shows to those they are trying to impress.