You know, at first I thought you meant real pool, and I got all excited...but not a swimming pool....heheh, oh well, I'm an evil j-rocker anyway, so I guess it excludes me. >
Well, I'm probably excluded just based on lack of owning a swimsuit, so I hold nothing against you.
Pro of the hotel pool is that there is a lot of tables, chairs and stuff on dry land. Cons include terrible acoustics and the inabilty to access the changing/restrooms without a room key. You could call the hotel and I bet they'd tell you about the hours of operation, tho.