As Mel Burslan wrote, the customers stand because arranging their stuff and sitting, then getting up again would make a normal simple interview take at least six times as long with the same result (I timed this more than once). Then the backlog would run even longer.

The window is for safety for the consular staff and officers. It and the wall it’s in are part of the internal hard line of the embassy. So no one can hit it hard enough to break it, it can’t be spat through, and the small teller slot underneath keeps people from trying to slide through thick folders of documents that the officer doesn’t want. Also gifts and bombs.