“translate perceptually similar” - keyword perceptually. What the video is explaining is that you should care who defines what perceptually is. I think a lot of people think these transforms are scientific. The math is robust where it needs to be, yes. The acesCG color gamut and general tools on offer are flexible and robust, yes. However the color transforms involved in mapping acesCG working space to your screen, are not guided by math or science they are guided by the perception of specific people with specific goals and subjective opinions (basically people making movies with certain aesthetics) that really might not make sense in your game or piece you are making or in a CG context in general. I didn’t care before, I tried the tonemapper on offer in the video and now I care, A LOT. It makes a massive difference and I didn’t realize how incredibly subjective the aces tonemapper is.
Use it and then use this tonemapper, just test it with one single point light with neutral temperature on a free meta human asset. You will immediately see that the aces tonemapper was not at all designed for CG applications in unreal and you will immediately wish there was more on offer to map the acesCG working space to your screen in a way that works with your lighting and cg assets.
Aces in general, great. Aces as it is implemented in unreal currently, respectfully and imo, incomplete and insufficient.