Daylight has a CRI of 100 because the sun is as close to an ideal black body as we're going to get. Perhaps absorption and reflection within the atmosphere lowe

Daylight has a CRI of 100 because the sun is as close to an ideal black body as we're going to get. Perhaps absorption and reflection within the atmosphere lowers it a bit, but I doubt it's significant. As for daylight containing lots of blue, I think that's the point - our bodies have adapted to recognizing blue as the defining characteristic of daylight, and keep us awake for it.