White balance usually corrects along the blue↔amber axis, often described as color temperature. But many light sources also have a green or magenta cast that color temperature alone does not fix.

That’s why cameras include a separate tint adjustment: it handles the green↔magenta axis, which is effectively independent of the blue↔amber one. In other words, a scene can be the right “temperature” and still look too green or too magenta.

The purpose is more accurate neutral color reproduction under real-world lighting, especially when the light source doesn’t match an ideal blackbody spectrum. So the controls are grouped together under white balance because both settings are used to make whites appear neutral and overall color look correct.