I dive with a watch, as a backup for my Suunto computer. Done many dives with my IWC Aquatimer, Rolex Sub, Omega Seamaster and PO... Which is nice to do, cause I like diving-watches a lot, but you should always remember that a cheap backup-watch like a Casio G-shock makes a bit more sense than go diving with a +5k piece, and if you do dive with a expensive piece, you should have no fear damaging or loosing it during a dive.
Makes no sense when a pushpin fails on that expensive puppy and it falls from you wrist into the deep, there's a danger you'd go after it then, which can be very dangerous or lethal. So, ask yourself this question, "Can you afford to damage or loose it, are you sure you won't go after it into the abbys when it falls from your wrist?".
If no, get a cheap Casio or Seiko to do the job.