Thinning out herds of wild hogs comes to mind. Seriously. They've become a destructive pest in parts of the US.
Shooting rabbits is also a thing that you might need lots of bullets for. BUT, you don't need such large magazines. Sure it is inconvenient to load up the magazines but, for such a small inconvenience it removes the risk of people using it on a crowd of people.
I would hope you don't keep shooting at a bunch of hogs or boar or rabbits that are furiously running away. You really ought to try and get clean kills. Reloading a magazine while the animals settle down, isn't a bad thing.
Semi-automatic long arms simply load the firearm without you having to remove your hand from the vicinity of the trigger.
And allows you to keep trying to aim (once the kickback is over)
I'm actually all for getting in rid of magazines entirely and just use bolt action. But of course in USA where you deem guns to be for self defence, that wouldn't work. You would need pistols/handguns with probably 6 rounds to be effective.
Although my argument would be that people are safer without guns than with. They won't have the confidence that comes with carrying so instead they will be more careful, also they can't have their own gun used against them, also the less guns in circulation means the "bad" guys will be less likely to have them, AND police will be able to take guns off people, if they are in public with loaded guns.
If you think that rapid fire is only a semi-automatic thing, look for the intro of The Rifleman. Of course, that rifle was rigged, and I think would be technically considered a machine gun in the US, but the rate of fire is real.
Good luck with being accurate with shooting while doing that.
My problem isn't the semi-auto mechanism, but the large magazines and even detachable magazines where preloaded ones can be quickly swapped back in. And I have seen those gadgets where they can have 6 rounds in a device and use that the quickly reload a 6 round revolver.
BUT, while people are reloading, then that gives others an opportunity to stop them or shoot at them or run away...