Pros
Unqualified people can have a long secure and comfortable lifestyle with lots of business class travel. They can fail upwards one promotion at a time, followed by a sweet pension at retirement. There's zero accountability if you wish to waste resources, terrify your staff or hire incompetent people. You can tell people at parties that you "work at the UN".
Cons
It's really amazing how many senior managers seem to have little respect for the mission of the organization or its staff. Some of these people seem to be truly oblivious or in denial to how bad things are... Claiming that things are highly successful despite all evidence to the contrary. Ignoring all advice from highly paid consultants and professional staff. Insisting that brain-dead cronies are highly qualified and deserving of their positions. There's also an undercurrent of meanness and cruelty to many managers that seems in part to force out anyone competent or who cares.