One common user case that arises from doing work for clients
is that they have an .xcf template and they want to change things about the template and export as .png, .jpg and/or .xcf

Each client is unique, but that's what I noticed so far that is common across many clients.

An example is for example you have a deck of cards where the background image to the card is the same the values on top is different, then you'd have your values in a .csv file. Then loop through the .csv grab values and change it for the template and export the card.
This is asked over and over again with slight variations since each client is unique. But it's efficient combination using excel .csv (really just any text file) and GIMP.

Another user case:
A client has an image of a character and wants to be able to select the hair, and hue shift it into other colors to change hair colors.
Without getting technical because of client's specs, this also can be automated.

A recent fiverr client review

Made a video clip of text to speech of this review (I collect 5 stars reviews like personal medals) hehe.

Another use case:
Client wants Auto crop layers to content without moving positions of layers, at first I did it but then their requirement was different it had layer groups. So I changed it to drill into children as well.
.xcf File size of the layers when cropped are a little smaller.