It's a good compilation of the side stories that take place, showing a little background on the team surrounding the goblin slayer, as well as showing the strengthening of friendship and loyalty among the group along the way. Also, since it's a side story, it shows a little bit of what happens when they're not on monster-hunting missions. There are only a few chapters, but they're very well done, so it's not a bad idea to read them to fill in some of the gaps left by the manga. If you liked the main story, I think you'll enjoy this.