LUFS measures loudness the way listeners experience it: level filtered to match the ear’s frequency sensitivity, integrated over time. The standard behind it (ITU BS.1770) ended the loudness war’s arms race by giving platforms a number to normalize to: stream targets cluster around -14 LUFS integrated.
Unlike peak or RMS, LUFS ignores what hearing ignores, weighting mids up and extreme lows down. Two mixes at equal LUFS genuinely sound about equally loud, which no other common meter promises.
Production now mixes to LUFS targets routinely. For visuals it is the right notion of long-term intensity: a whole-set energy arc is a LUFS curve, even when nobody calls it that.