Well, Jung dealt with the neurotic mind. And psychotic too. He lived in an age when psychology took its baby steps. To prove his most important ideas he had this period of 'drowning into abyss', whatever the exact wording might be, it is a relevant subject to look deep into, since unconscious plans play a role in satanism too.
For example Satan represented unconscious motivations for neurotic people in 1960. Well, Jung also told that neuroses and psychic 'disesases' generally are WINDOWS TO THE SOUL OF MODERN MAN. You could take from it that it is healthy to be a little weird, trying to make your own relationship with Lifes restrictions for example.