with the current implementation of the UploadHook solution (currently checked with FirstSpirit 5.1 R2 209), FirstSpirit always creates a new revision of the processed element by executing a save-action at the end - whether this step is useful or not.
Imagine, the goal is to get a released element finally. With the current FirstSpirit core implementation of the UploadHook solution, the element stays in an unreleased state at the end. Although, the processed element has been released within the code part of the custom UploadHook. Details can been shown in the following screenshot. There, it can be proven that the save action is not implemented in the custom upload hook solution but executed by FirstSpirit core:
This is not very useful.
That's why this feature request votes for omitting the implicit "save" action and give the developer the responsibility to decide if and when to save.