After reading most comments I re-watched the video to confirm my understanding.
Most commenters seem to have missed a few points:
1- Seth cares about color management both in his workflow and in his creative process,
2- he shoots with multiple bodies within the same photo shoot and observes color inconsistencies,
3- in his case and for his workflow, the color checker fits in as another-good-tool.
4- by allowing him to align the color of all his shoots in about a clic, it saves him time in post to focus on the artistic side.

Lets talk video.
Imagine yourself at a soccer match, 10 to 15 live cameras, sometimes from different brands, each shooting from a different angle, with different lenses, receiving a different light. And when you sit in front of your tv, all looks consistent. How? Color management and calibration.
As a video cameraman, I can tell you that without color control and calibration it’s impossible to shoot a multi-camera event and have consistent rendering. Even with only two camera.

Continuous color management doesn’t restrict us creatively, it’s just the opposite. And btw, by giving us a consistent and known base, it saves us an insane amount of work in post-production.

It doesn’t mean color management is for everyone or for you. It just means that in some industries it is a must and that the color checker is a nice-to-have tool if it matters to you and your business.

But one thing he did say was the following: he shoots a lot of fashion, and by using this he never messes up the colors of the clothing, they are accurate. Because of this, he never has any problems with the designers, which he did have in the past on some occassions.