Thanks for sharing your thoughts, it is a good little prop. Do you have a unique presentation?
This is a prop I have been using for years. I like to use a rubberband to seal the "business card holder" closed so "know one can possibly see" at that point as I wrap the rubber band around I get the "peak"
I also like to present the transmitter as a business card holder and will do a few effects just using the cards until I run out and need to use the writing pad included.
I think it's important to "condition" the spectators by using it in different ways besides a peak- i.e. record a prediction with it, or write something down that you don't want to forget- this conditions the specs that you are just using an erasable writing pad.