The Placard is primarily used to display items for decoration. It emits a short Redstone pulse, the same length as a stone button, when right clicked with the same item it is holding. Unlike Item Frames, it will stick to Contraptions, and items cannot be rotated once placed inside. The Placard also does not interact with the Comparator; there will be no redstone output regardless of whether or not an item is inside the placard.
A Placard, and the noticeable lack of interaction with a comparator.
A demonstration showing a Placard being activated by a Deployer.
