Translucency is not a fake implementation of some other feature. It is different than SSS. The black/white/green whatever you set is a COLOUR value for transucency, the other value is fraction. If you set translucency colour to black, then black colour will blend with diffuse. At least that's how I understand it.
If darker translucency colour would mean less translucency fraction, then how would you make a very translucent material that is dark?