In the downtown area where I work there is a Nike store that has had a sign in their window advertising a shoe "so fast it comes with an airbag". I find the advertisement amusing partly because I like to image an airbag inflating in someone's face if they stub a toe but mostly because of a mentality that assumes that power is granted by an object. Magic is full of this. I constantly hear talk of which grimoire is the most powerful, which tarot cards the most accurate. It's like asking a couple of kids whose bicycle is faster. Sure the performance of one bike may be more efficient or it may be lighter than the other but that is not the source of the power of the bike. The power comes from the strength and determination of the rider.
The same can be said of grimoires and tarot cards. The effectiveness of both of these items have less to do with their content and more to do with the conviction of the practitioner.
Let's take the case of the Simon Necronomicon. This is a book mostly based on the fictional works of H.P. Lovecraft. It was published in the late 1970s and was a mix of Babylonian names, invented sigils, and material from Lovecraft's writings. It has no pedigree or ancient lineage. But people have gotten it to work, contacted its spirits according to the procedures in the book, and it has spawned a subset of grimoiric magic all its own.
Why are there Hello Kitty tarot cards that people are able to use effectively? Because the content is secondary to the practitioner.
Content is secondary to the practitioner.