Aggie, the numbers are just to illustrate a point. Actually if anything I am more on your camp after having done all that sensitometric rigamarole. When I first started , like many I wanted to make pictures like Ansel Adams, and I thought a thorough understanding of sensitometry was required. So I did all that, and I learned a lot, but now I am back to developing by inspection, etc. The one advantage of having learned all that was that I know what a good negative should look like, and how to obtain it, but it is not necessary to make great prints. As far as I know Edward Weston never came withing 100 feet of a densitometer.
If you learn sensitometry you have a greater control over your materials, which I think makes expressing your "idea" or vision easier, but by no means it is essential, I think Michael Smith does his contrast developing by the "glug, glug" method.... he adds more activator to the ABC formula as he thinks is fit, he does not do all the sensitometry.....of course with his experience he has probably made all the mistakes there is to make and knows what to do by intuition.
So dont get bog down on the numbers, is like the coffe cup holder in your car, is nice to have but not essential to the operation of the car.