when do we use HSV color space and when do we use CIE-Lab color space?
HSV has very intuitive axes (hue, saturation, value) and is useful for manual choosing and adjustment of colors. It is defined in relation to an arbitrary RGB color space.
In CIELAB, only the lightness (L) axis has an intuitive meaning (in my opinion). Euclidean distances in CIELAB coordinates approximate perceptual distances of colors, which can be useful. It is defined in relation to the CIE 1931 XYZ color space, given a white point.