I'm not a great hunter. Or, really, even a great shooter. I mostly hunt small game, birds and such and around here the places to go and the pickings are slim, at best. So, eventually I figured out that I go hunting in order to go hunting. I go hunting to be outdoors and have fun. I began to experiment a bit more. I have been lately hunting much more with single-shots and with inexpensive double-barrels. I tried my 28" Spartan SPR220 but realized quickly if I'm going to trudge through the fields and the woods for perhaps several hours and probably shoot 0-4 times, that gun "feels" heavy, muzzle-heavy to me, i.e. my Winchester 1300 with synthetic stock carries better. OTOH, a Spartan coach gun carries in the woods and brush like a dream. An NEF single-shot, though longer, still carries like a dream and really doesn't kick nearly as much as people go on about, especially wearing a heavy coat and only taking a shot during the adrenalin rush of a flush. I carry an extra shell in my left hand and practice getting a reasonably fast reload but I'm aways off matching the old-timers at that. I figure, if I have one shot and miss, it's a good day for that bird. If I have one shot and hit, I have hunted. No different than if I were bow-hunting with flu-flu arrows.
To me, there's no reason not to keep the technology in line with the game. Simple. I mean, it ain't about my survival but about my enjoyment. I've heard a pheasant flush in the field and it sounded like the skies over Baghdad during the First Gulf War. Poor bird! Even then, some of them get away because the hunters sprayed better than they prayed.
In the future I plan to hunt quite a bit with both a coach gun and single-shots. If someone looks down their nose at my choice, not my problem.
If I can't have fun with this stuff, I wouldn't want to do it.
But, back to defense. I think any firearm that we use enough to be comfortable handling, shooting, reloading, etc., is viable for defense. Ergo, hunting, clay-shooting, etc. are all good things to do with the gun, or the type of gun we plan on using for HD.