one use case is when you're loading a well formatted LO writer document.
the first line is the heading, then comes the lead and finally the text:
- you can have three text frames that are linked,
- placed in a default ok place,
- load the whole text into them,
- tweak them in a way that the text is in the right place,
- unlink, while leaving the content in place.
now you can freely modify, resize, move around the frames without fearing any reflow...