Tbf, hadn't realised it was based on a novella. Regardless, it was pretty sloppily written and unengaging, I don't mind keeping her relevant in a season based on a book she barely appears, just have slightly higher expectations than what we saw.
I expect it'll pay off in the new season...
The way they've been doing the TV series has been to mix and match certain parts of different books, so some things that paid off in a single volume of the book don't pay off in a single season because they've taken the decision for the TV (from what I can tell) to show things concurrently, from memory the books tend to concentrate more on specific people/locations at a time so in some cases you've got events in two books largely overlapping but only mentioned peripherally in either book if at all, then the novellas fill in some of the background detail/add more to what happened between books.
It's about the only sensible way to adapt books to a normal TV series, without mucking around with flashbacks, and one of the things that any showrunner/TV writer tends to have to look at doing if they're adapting a long series of interconnected novels, novellas and short stories into a coherent TV series.
I actually quite liked the Bobby on Mars arc from a technical/story telling POV as it potentially solves some issues they might otherwise have had in showing what was going on leading to upcoming events - think Babylon 5 where what seemed like minor events in season 1 or 2 become more important in later seasons, it also potentially fixes an issue they might have run into with the character in later series. Bobby in the TV series is from memory a combination of two characters from the books who have been merged and fleshed out, which can cause problems for continuity if you don't add something to join the character arcs.
Talking of the Expanse, I finally got round to reading a couple more of the shorts/novellas the other week and they made a difference in understanding what had happened between a couple of the books, and the background of certain events/characters (for example "Strange Dogs" which gives some useful/important information on the main planet in Book 8 and a couple of the characters).
And now I'm getting the urge to do an Expanse reread, this time doing everything in order as it's been ~5 years since i last read a couple of them.