Regarding point A:

Based on our experience at Columbus Rationality, I think that having people think specifically about various life domains helps analyze and improve those life areas. My take is that habitual application of rationality is only one aspect of agency as such. I believe tha to know where to apply one's rationality skills to improve the situation, it is vital to have a framework of thinking about specific life domains.

Regarding point B:

I think your criticism is appropriate here, and that's why I presented the article as the start of a research project, not the definitive conclusion. The case study of yourself with the game you brought up is exactly the kind of response that will help build up further case studies and provide fruitful ground for further research that will enable a more fine-grained understanding of various life domains and agency in various ones.