I can give you one example. I have found that for my particular camera the colors are slightly oversaturated consistently. For each of the three colors I find that it was necessary to adjust the color saturation to a -20, and make that setting part of my default settings. Now, when I import images into Lightroom Classic I find that the colors are much more to my liking.
As I mentioned, this is what I discovered for my particular camera. It may not be the same for your camera. It may not be necessary to make any adjustments for your camera. But if you find that you are consistently having to modify color saturation for other color settings that can be modified in the calibration section and made part of your default settings, it can simplify your postprocessing somewhat. Don't know if that will help, but that is how I have used the calibration panel.
Legacy panel prior to the introduction of .DCP (.DNG) camera profiles. Yes, you can futz with it and produce effects you may desire, or completely ignore it and instead use provided (or better custom) camera profiles. See:
Everything you thought you wanted to know about DNG/DCP camera profiles: All about In this 30 minute video, we will look into the creation and use of DNG (.dcp) camera profiles in three raw converters. The video covers: What are DNG camera profiles, how do they differ from ICC camera profiles. Misconceptions about DNG camera profiles. Just when, and why do you need to build custom DNG camera profiles? How to build custom DNG camera profiles using the X-rite Passport software. The role of various illuminants on camera sensors and DNG camera profiles. Dual Illuminant DNG camera profiles. Examples of usage of DNG camera profiles in Lightroom, ACR, and Iridient Developer. Low Rez (YouTube): http://youtu.be/_fikTm8XIt4 High Rez (download): http://www.digitaldog.net/files/DNG%20Camera%20profile%20video.mov