Unfortunately the original thread was locked so I opened up a new topic to comment. And you are correct there were some great replies to various aspects of the video @Theo.
A video that quantifies the total fixture output (integration of illuminated energy in PAR region) and then correlates PPFD measurements, with sufficient sampling, would be a more accurate comparison video. PPFD measurements with varying fixture heights hold value in describing how the fixture output is distributed over a given area. In this context, I’m stating these videos do have merit in education and product differentiation.
My point is simply that with these comparison videos, manufacturers must be careful in presenting this information to the community, especially fundamentals, correctly. Grow light comparisons in terms of light quality, light quantity, and radiometric distribution allow growers to make an educated decision on what fixture is best for their space. As I prefaced in the original comment, this is a challenging subject! Mistakes will happen and we the community have the ability to vet this information. An open comparison and discussion over clearly defined metrics and testing methods is tremendously beneficial to those using the products.