Do you never find yourself choosing to go to a slightly less upmarket, but more buzzy and popular bar over a very luxurious but quiet one? I certainly do - sometimes you want quiet, sometimes you want busy. More to look at, for a start

Standing/seating arrangement differences aside, there's going to be almost no-one at the F bar, whereas the J bar is likely to be much more busy at any given time. If you want a drink by yourself, you'd just stay in your suite - but if you want to hang out with other people, you'd go where there are more people. Which is the J bar.