How is it used compared to, say, a written standard?
For example if you are a company that has lab equipment that analyzes the nutrition content of a food sample, they could use this peanut butter as a reference sample to make sure their equipment is properly calibrated.
The Veritasium one mentions NIST peanut butter specifically, even.
Let’s say you are a large food producer and you have to make a pb&j sandwich. You are going to do a great deal of measurement, taste tests and other experiments to verify your sandwich is what it says on the box. Also packaging will be highly dependent and also even the nutrition label. Do you want to worry in the design phase that your sandwich has a variable consistency and weight ? No .
The ability to put Facts on a "Nutrition Facts" label.
Its used for calibrating their instruments (or to validate the calibration of their instruments), which are THEN used to report on their products contents, which if they are found to be sufficiently in error there are adverse consequences.
Having a reference material whose composition is very certain is important here.