It is not a job, regardless of whether or not you have to fill out an application.
It is a volunteer position that staff take upon themselves to get experience, to have fun (in some cases) and to help keep Graal running smoothly.
One does not just get promoted to the PWA (Global) team after X amount of years. The Global's hardly ever recruit, and if they do I'm sure they have a list of people they're interested in, and wouldn't necessarily recruit from playerworld/commercial staff.
I wouldn't imagine globals being paid, I imagine it's a volunteering job not unlike our own.