That “damn densiwhatsit” allow you to predict roughly how a print will look like. If you examine that technique, you can actually say good-bye to the test strip and you will need significantly less trial-and-error attempts. Learn to print and save a tree.
However, this is just a technique or “an abstract tool”. You still have to have an idea of what your print *should* look like. It is not a substitute for any creative action. It is just a more systematic method of working.
Experience might of course be an alternative. However, it will take you much longer to get there. Knowing the basic principles behind Photographic Techniques will allow you to draw much more conclusions than just knowing how to select the right paper grade for a negative.
There is an explanation for every photographic effect, even the apparently mystical ones. I have to accept that not all people like such demystifications, especially in the context of the arts. I, however, always wanted to know why something is the way it is.