FWIW, I've gone through a few hundred rounds (in the neighborhood of 5-600) of the Sig stuff, and I've found it wildly inconsistent. There would usually be 1 to 3 rounds in the box of...20? 25? That were underpowered; enough so that the gun barely cycled and the brass just kind of plopped out the port of the 1911. There'd also be the other side of that, where a couple of rounds would really light the world up. I never noticed any overpressure signs on them, but you could feel the energy difference.
Admittedly this may have been older ammo; the last time I spent any appreciable amount of time shooting Sig 38 Super was maybe 4 or 5 years ago at this point so their load quality may have improved since then.
YMMV and I probably wouldn't mind using it for defensive purposes, if I could guarantee that the loads were consistent.
I bought a couple hundred rounds of Georgia Arms 38 Super 124gr Speer bonded HP loads for defensive use a few years ago; I've got maybe 75 rounds of it left. Very consistent stuff...sadly it looks like when the ammo crunch hit, GA took it off the menu to concentrate on less hipster loads..