Why one color needs multiple formats
HEX and RGB describe additive screen colour. HSL and HSV reorganise the same underlying colour into controls that feel more intuitive when you are nudging hue, saturation, lightness, or value. CMYK is a subtractive ink model used as a print reference rather than a direct screen description.
That means the same colour can be validly written in several ways at once. A good converter does not create a new colour. It normalises one colour so every downstream tool sees an equivalent representation.