Every single athlete I train press standing... except bodybuilders!!! Most of the bodybuilders I train or have trained pressed seated at a very steep angle (back seat at about a 80 degrees angle). The reasons are:
1) Most do not have the shoulder mobility to press at the right place (bringing the bar behind the ears when the arms are fully extended). They press the bar up and it stays in front of their head. The seated position makes it easier to press more weight when you press forward.
2) It's not a jab at bodybuilders, but is is a fact that they are much less stable and coordinated (in general) than athletes and because of that they use much less weight, with worse form, when pressing standing.