Yes, they can be valuable on 2 levels:
1.) General guideline on how your health/endocrine system is being affected and once that's satisfied;
2.) Guideline as to where you need help with your supplement selection.
For example, after satisfying objective #1 above I ran a cortisol, testosterone/free T test. Knowing these #'s revealed that I could benefit from an ATD/ActivaTe stack. Otherwise, I might have wasted a lot of time and money on pursuing other area such as adaptogens, anti-cortisol products etc..