As someone who has had a casual interest in card magic and sleight of hand, here’s an observation about how so many different tricks can come out of such a seemingly simple sleight.
There’s a fairly simple formula that makes it possible to be very creative and come up with endless new tricks and variations.
At the heart of any trick is some sleight, such as the double lift, where the illusionist creates a seemingly trivial rift between reality as the audience perceives it, and reality as it actually is.
The illusionist can then get creative with what to do with this difference.
Usually you maintain the facade and do things that would be possible in both realities. From the audience’s point of view, it’s like the trick hasn’t started, when in a sense it is already over. Then, at a safe distance from the original sleight of hand, in terms of time and attention, the illusionist can now seem to break the rules of the reality the audience believes in, simply by revealing the difference between the two realities.
This allows you to amplify an underwhelming “Ok, so I couldn’t see that you picked up two cards” to a very impressive “Wow, my card magically reappeared at the top of the deck after you put it into the middle of the deck and let me shuffle it”.