The gist of the post was that only the cards of the Major Arcana (trump cards) were complete and usable in this deck. However, I found a great use for just these cards in one of my books the other day.
The book is "Exploring Spellcraft - How to Create and Cast Effective Spells" by Gerina Dunwich. In chapter 4 of the book, called "Divination Before Incantation," she explains how many Witches do divination to determine the probable outcome of a spell before casting it, to make sure it's worth doing. She then explains how to use just the Major Arcana to do this, and gives explanations for each of the cards based on their traditional meanings, but with the idea in mind that the question asked is about spellwork. Both the upright and reversed meanings are addressed.
How cool is that? Guess I know what I'll be using that crazy deck for now!