Ever thought that the vanilla vendor stalls just felt empty or lacking? I mean, aside from slight visual differences, they all felt samey. Immersive vendors fixes that by adding variety to the vendor stalls you can build at your settlements. It also populates the higher-end stalls with higher quality items to reflect its store level.
It's a minor mod but to me, it's all about those little details, especially since I really enjoy the settlement building aspect of Fallout 4. I also tend to spend a lot of time with setting up my settlements to look busier and more populated, so this mod is a big plus for me.