Vray BumpChannel Vector3?

[Khazmadu]

Why exactly is the BumpMap input of the VrayShader a Vector3 and not a Float? Is there any situation in that you would use different values per Color Channel for a Bump Map?

[yolov]

Vector3 usually means a set of 3 float values (i.e. a vector) that represent a color. 'Float' inputs are usualy a single float value (for example alpha that's plugged in reflection glossiness).
You would ned vector3 for normal maps.