The objective here is to quickly and easily replace the underlying table occurrence context of a field on a layout.
It is so common to have to repoint multiple fields on a layout to a new context (more common than you think). Right now you have to select each individually and manually choose the new TO from the list.
The context is always the same underlying base table, so it should not be hard to just alter the underlying TO, the field should still map correctly.
To be able to copy/paste a context ala format painter, or some other means to apply a context to multiple fields will save a lot of time.