Pro-tip: when searching the Quixel materials for the first time it’s easy to get the wrong Dirty Concrete Wall texture. The one shown in the video is found most easily by going to the sidebar and picking Surfaces - Concrete - Cast In Situ and the correct Dirty Concrete Wall is right there as the first result.
There’s not really a right and wrong one, only different. You don’t have to use the same texture as in the course.
Of course, if you want to, you’re absolutely right.