On phone...haven't been on for a little while as life has been rather full on.
Anyways...
I carry them with me all the time, but have never considered any of my readings as being "predictive" really even with a time frame.
I think the person above is right - I remember in one practise circle with them some did it with and/or without the book.
I like the book as it does add substance and some cards are not literal just because of the word or picture on it. Eg Inheritance.
Of all my decks I love the Lenormand, Mystical Kipper, and Psychcards the most and these I have tried together (they compliment one another rather well)
and are my main go tos.
Love a few others too for different reasons.
Psycards are excellent especially for Psychological stuff, but they are not limited to just that at all.
Maybe by itself it is enough for the Psychological and with other tools it could add to predictive.
Nothing is set in stone no matter what except taxes and death.