I have heard and read many folks touting the virtues of the 148 grain full wadcutter for self defense use particularly from a snub nose revolver.
People have all sorts of ideas and paradigms they've created through imagination. While uncalled for confidence in a load isn't necessarily a bad thing overconfidence can be fatal. The wad cutter is a poor choice for a self defense round in any barrel length when compared to other available ammo that at least has some track record and lab testing. Many people have used .22 LR solids to defend themselves and kill other people but that doesn't make the .22 the best choice either.
The wad cutter makes a great paper punch hole in targets making for easy scoring but as a SD round its simply the imagination of the flat point damage that gives it the small fallowing of users. Its unlikely its any better than any solid bullet of other design from LRN to FMJ. Not that it won't work in a SD scenario just not any better. If you want a lead bullet with a decent record buy some LSWCHP's from Speer or Hornady and load them with +P data to achieve near 800 fps from a snub nose for something better.