There was no guesswork, or work of any kind really, in sewing these pieces together. This piece of embroidered fabric obviously was intended to be a pocket, so a pocket it became. Adorned and embellished, but still useful.
In olden days pockets were made separately from garments. They were given as gifts or purchased, and then sewn into an undergarment. The things you might find in a pocket back then is quite astonishing.
But pockets can hold anything really. Even memories. Things worth remembering. Notes, words, or fragments of memories, that over time might be lost and forgotten.
But if you can’t trust yourself to remember, you can always use a bookmark.