Sometimes animation clips need to corrections to resume a posture from the legs, arms, torso etc specifically - like taking a specific snap shot of a body part or parts in one clip and pasting it to another. Currently "Set as Default" only takes a snapshot of the entire pose. In the future it would be good to have/be able to create a library of snap shots in the same window that users could choose from for fast iteration. These posture snapshots would save and access to a folder (ideally your Avatar or scene name) but can be used quickly with the Edit Motion Layer. To simply drag in a pose can delete your existing one so this snapshot/pose stamp tool makes sense.