There are good reasons to settle for a less expensive configuration other than cost. Systems with less powerful components have less heat to dissipate and are therefore more likely to run cooler and quieter than their more powerful alternatives. The ROG GL504 series is the latest example of two visually identical SKUs with very different performance profiles.
https://www.notebookcheck.net/The-Asus-ROG-GL504GM-Hero-II-runs-cooler-quieter-and-longer-than-the-GL504GS-Scar-II.328488.0.html