If I'm throwing a brick or a car at someone it is not hyperstrength that helps me hit the person. Hyperstrength only helps me do more damaged if I do hit. Therefore, there is no contest.
But you do bring up a good case that is a fine line. If you don't like the rule, then change it.
As to the defensive question. "Some" is the key word. SOME always on powers can be used. Immunity can sometimes be used but not always. Say you have two talents: one has a flamethrower and he can enhance the flames to make creatures like dragons and stuff. The other can shoot flames out of his hands and buys it as harm.
Someone with immunity may not be hurt by the first talent because it is after all just flames. But the second talents flames are actually a harm power that manifests as flames. So they aren't really flames in a true sense.
That's one way to read it.