For sporting use I agree the cartridge is pretty worthless as a genral purpose round, of course if you work hard enough you can find something it can work for. Killing deer and turkey with pointy sticks seems to be in vogue at the moment so surely you can find some huntng use for the carbine if you try hard enough, coyotes come to mind.
Huntings not the carbines strong suit anyway though. I've had a Winchester (GI) carbine for about a year now and can say it goes to the range more than any of my other guns. Low recoil, fast shooting, much more accurate than you would expect, fairly cheap ammo, and very easy to hit with off hand. Whats not to like? It's really about the funnest little rifle you can own I wouldn't trade mine off for anything short of Cindy Crawford.
By the way you will hear a lot of talk about how enemy troops absorbed dozens of direct hit's with M1 carbine rounds and batted them away like pesky insects. Well.. Audie Murphy likely saw more combat than about anyone who post on this board and he liked the M1 Carbine, so I'll let that speak for itself. Also Jim Cirillo(sp?) of NYPD stakeout squad fame reported that the Carbine loaded with softpoints was the only weapon (sawed off 12 gauges with buck and slugs included) that stopped everyone he ever saw shot with it instantly, no follow up shots needed. So if your thinking of using one secondarily as a defensive rifle there are at least some in the know who would'nt critisize your choice.
Basically just a great little rifle, I have no exp. with anything but the GI guns so I can't help there, but reccomend you get one while you can.
Regards, Blue Duck