First up, don't expect the whole 80-pages stated in the Kindle book details. The story runs to about 60% then it's an advert chapter for Ann Leckie.
Second up, while it is set on Laconia, don't expect to meet any of the known Expense characters, apart from a cameo by ex-MCRN Admiral Winston Duarte.
Third up, this has a different tone to the mainline novels. In particular, it is through the eyes of Cara, a young girl who only knows life on Laconia.
Being a short, it's hard to really critique without giving it away, but let's just say Cara stumbles on to some amazing/horrifying aspects of the local wildlife and uses it to right a wrong. Of course, being young, Cara is not to know that such things hardly ever go to plan, and tears typically result.
I liked that Cara is well portrayed, though she is perhaps wiser and more mature than you'd expect. That's needed to drive the story and is not a major issue. The rents are barely there, as would be expected in the circumstances, until they are totally there and suddenly wondering what they did wrong. And the implied tension between the civilian population and Duarte's soldiers is neatly done.
This short fills in a few fine lines that are revealed in the immediately last Expanse novel (think it's Book 7 from memory), but you can read it out-of-order, it is neither a reveal or compelling knowledge for the mainline sequence.
And that's probably the take away. It is interesting, but it's not really an "Expanse" story in that sense. Indeed, apart from Duarte and your knowledge of the protomolecule from the mainline, it can easily be read totally standalone as a kind of "new to this alien planet" horror story.
So a fine tale, the basics of which a master American horror author writ large decades ago, but not compelling or necessary.