Yes. If you're a fan of the series, it's definitely worth reading. It's the conclusion of the story you've been following, so it's like getting the final piece of a puzzle.
Kazuma is a key character. He's a normal guy from our world who has to adapt to the crazy Konosuba world. Aqua is the goddess who brought Kazuma there but is often more of a hindrance. Megumin is known for her love of using explosion magic which has its own set of consequences. Darkness is the crusader who has some rather unusual, masochistic tendencies. These four characters are at the center of the story in 'konosuba last light novel'.
We can expect a conclusion to the story. It might tie up loose ends regarding the characters' relationships. For example, we may finally see how Kazuma's relationship with Aqua, Megumin, and Darkness fully develops. It could also introduce some final grand adventures for the group, perhaps a battle against a powerful final boss that has been hinted at throughout the series.
We can expect an exciting conclusion to the Konosuba story. It might have more of the hilarious misadventures of Kazuma and his party. There could be new challenges for them to overcome, and perhaps some unexpected character developments. Maybe we'll see more of the unique magic and skills in the Konosuba world.
I'm not entirely sure, but it's very likely. TvTropes is a comprehensive database for all kinds of fictional works. Given Konosuba's popularity, especially in the anime and light novel world, it would make sense for there to be a section about its visual novel on TvTropes. You could check by searching for 'Konosuba visual novel' on the TvTropes website.