Yes, in fact parametric blending in combination with drawn masks are very powerful way to mask and influence local areas of the image.
But there are some differences between this masking in the darktable and control points:
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sometimes in the darktable it is not so easy or very tedious to mask a certain area (in this case brown skin of people) - it is possible but not so easy - you have to combine more channels of parametric mask together (color, brightness etc.)
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if the different areas in the image that you want to change differ from each other, you have to treat them separately by activating multiple instances. In Viveza or Snapseed each control point can be handled individually without having to activate additional instances for each point.
Comparison:
Masking in darktable:
and in Viveza:
So, in darktable you can, if you try hard enough, work very precisely, but with the help of control points you are in many cases simply faster and more effective.