DDC will adjust the brightness of the backlight of the display itself and thusly will result in superior calibration results.
DDc is far more complex and flexible than this suggests. On many monitors you are actually adjusting the output to the backlight so you can control brightness contrast and color. In more cases of late, monitors have 10+bit internal luts providing a wider range of adjustment without losses like we see making video lut adjustments
Unfortunately, proper support for DDC is not as common as it should be.
Absolutely. the biggest problem at the moment is monitor and video card manufacturers stating a product is ddc compatible without any more information. There are countless versions of how ddc is applied and what functions it actually controls. Then there are monitors like the eizo employing an entirely different scenario that can't even be called ddc. All of these variable are not only giving us the customers fits but software developers, I can tell you first hand are tearing out hair in large clumps.
