Compressionless won't really raise your brake power. But it'll make the feel at the levers a lot nicer. As in firmer with very little give as you squeeze harder.
Since you're using cable brakes I'll assume that the caliper itself has one fixed (but adjustable) and one movable pad. When I was using cable discs I found that stopping power was raised strongly when the fixed but adjustable pad was set up to run as close as possible to the rotor. This means fairly frequent tuning but it makes a huge difference. When set up really nicely you can get almost hydro brake like power from your braking effort.
The why of it is that when the fixed pad is running too far away the movable pad has to use up some power just to flex the rotor over to pinch it against the fixed pad. And when it flexes like that it only touches on the outer edge while the movable pad only touches on the inner edge. Then as you squeeze harder you flex the rotor more and more until it's has an "S" bend in it with the pads in full contact. But it takes a fair bit of your effort to do that flexing. And that's effort which isn't going towards stopping. So the closer you can get the fixed pad to the rotor the less power needed to let the rotor flex to full contact.
If all this sounds like a lot of fussing with the brakes? Yep, it is. But after a few times and some initial tuning to tweak the rotor so it runs super true it's pretty quick to do.
And when you match up a nicely set caliper AND the compressionless housing you'll really smile at how well the brakes do work.