And yet, near completely useless as shown by cases known to wide public.
If you think blackmail is the only thing that can compromise a man, you have a lot to learn about life.
History: some of most baffling espionage cases were "walk ins"
I think, it is the type of personality that services all around the world seek – somebody brilliant, but easy to guide, and motivateable with BS pretenses, that itself makes such people to seek to play with fire.