Because after seeing a video by f64 Academy, he showed how powerful it is. I tried it on an image in LRCC and really liked the results. I have the same image in LR CC with all the same edits but the Calibration ones, and wish it was there.
You can do some of the same thing with the Color section, although you'll have to pretty much apply the adjustments on an individual image basis. I used the calibration section in LrC to tone down the saturation globally for one of my cameras.