I'll give you an example - pest control. I own a property about 100 kms West of Ottawa, and spend a fair bit of time walking it with our three dogs. The area that this property is in is practically overrun with Coyotes. So, I purchased a firearm (a Ruger PC Carbine, in 9mm) that is semi-automatic, specifically because when a Coyote comes out of the bush on a run, going for your animals, you very likely won't hit it with the first shot, and follow-up shots with a bolt gun, or even a lever gun, are slower than with a semi-auto. The reasons for this are: 1) it takes time to cycle the action, and 2) additional time to re-acquire the "target". By the time you are able to take a second shot, it could literally be too late. A running Coyote is a hard target to hit, and having to stop and load another round into the chamber "manually" makes the chances of a successful hit on a follow-up shot much much harder. This is where a semi-auto comes into its own - in situations where a fast follow up shot (or shots) is needed. I would add that even in standard hunting situations, sometimes having a quick follow-up shot is the difference between an ethical kill, and a wounded animal bolting after being hit and dying a painful death somewhere in the bush. There are many semi-auto rifles chambered in popular center-fire hunting cartridges like .308, .243, and .270. The Browning BAR is a good example of a popular semi-auto rifle used quite extensively by hunters.
The annoying thing is I purchased that Ruger PC carbine after very careful consideration about what the government might at some point in the future try and ban as an "assault style" weapon. This is a pretty ordinary looking firearm, with non-tactical stocks, firing a low-power (by rifle standards) round. It fit the bill for me, as I'm only looking at distances of 50-75m, typically, and a 124 grain 9mm is more than adequate for Coyotes at those ranges. But, I see in the recent amendment to C-21 that this rifle is on the list, so I stand to lose it if this goes through. The irony of this is that for my particular "use case", an AR platform in .223 would be the ideal solution.