They rise into a cadent House though, which supposed to be a weak position compared to an angular House.
It is inoperative, because it is declining from an angle. Personally I regard the 12th as more operative than the 6th and 3rd though.
Angles are the places where the planets reach their maximum influence and where they directly strike the place of birth, though I follow Ptolemy in regarding the Dsc and Ic as weaker than the ascensions and post-ascensions of the Asc and Mc (1,2,10,11), for the qualitative (Dsc) and quantitative (Ic) reasons I mentioned.