The dozen or so short stories I have written that tie into my book series cause me confusion by
a) introducing some characters that don't appear until later books, and b) making it hard for me to remember what has or hasn't yet happened in the books I'm working on (but may have happened in a story).
In addition to these difficulties, I have realized a great benefit to writing these stories. Through them I have a much stronger understanding of my characters.
There are at least two reasons for this. One is that the plots of short stories can be a little more unusual than one I could use as a subplot in a novel. And in more bizarre or intense situations, you get to see sides of your characters you might not otherwise encounter.
The other reason might be particular to me. I write my Daylight novels from the first person perspective of the protagonist, Helen. Some of my short stories are also written from Helen's first person POV. However, a few of the stories are written from the first person POV of different characters and some are written in the third person POV of other characters.
This may be an unusual way to write a series of short stories and I don't know why I do it. I don't consciously think, "This would be more interesting if I used this or that POV." The stories just presented themselves to me that way. And that aspect of my story crafting falls under my philosophy, "Write in the way that works (best) for you."