The gilder's cushion seems to be more European than American - Ray LeBlanc does not even mention it, and he is pretty wide-ranging. I made mine when taking a class in manuscript illumination: most of the time you are using pieces about 1/8" square, so being able to cut the leaf up was important. Since then I have found a few signpainter uses for it, such as cutting thin strips when you are gilding, well, thin strips. Or when you are doing incised letters, say vee-cut tombstones: lay two leaves down on the cushion on top of each other, then cut them into pieces. The pieces will (mostly) hold together at their edges, and you can lift a doubled piece of leaf with a brush and push it into the sized vee-groove - the first layer will hang up when it touches the size, but the second will slide in and go to the bottom of the groove.
People who learned on the cushion seem to like it a lot - I saw a movie of the restoration of the Statue of Liberty, and they mentioned that they brought over a gilder from France to do the torch. The torch flame looked about six feet tall, and he was gilding it with a tip, using a cushion.
This is from "Practical Gilding, Bronzing, Lacquering, and Glass Embossing" by Fredk. Scott-Mitchell, London, 1914. It is a funky xerox copy that the Society of Gilders was selling. Note also the knife, which they require to have a straight edge to the blade, I've never figured out why.

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It looks pretty much like Dave Smith's setup, from his video:

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