Bottom heavy ... does that translate to better shadow detail? Sorry, I'm not familiar with how to read/understand these plots yet. They look pretty tho'! - I have purchased ColorThink and played around but it's still a bit beyond me.
I don't think that it necessarily means more shadow detail, just that there are more dark colored crayons available in the box you are coloring with. It is able to reproduce more darker tones, so the assumption would be that this will afford more ability to distinguish detail in shadows, with a wider hue variety possible in the darker color ranges, but I don't think there is a direct link between shadow detail and a substrate's gamut. Either way, it can't be a bad thing.