Most of the pro level cannon wide format printers now have 10 or 12 inks. Once you get above the $1000 price for the printer and into the 17" and wider printers will see wider printer heads that can handle more carts. The additional carts are used to increase the chroma levels in the darks and to prevent banding. Often there’s a gloss optimizer which helps with gloss on certain colors. Many times these are the printers you see behind the counters at photo printing labs.

Eight is really a bit much. Most I’ve seen was 6 on my parents old HP Photosmart C7280. They’ve added lighter shades of magenta and cyan, supposedly because it looks better on photos.

But it’s an HP printer so that’s probably not the main reason…

light cyan, light magenta, light black, and light light black.