I'm no expert on this, but I thought I'd weigh on what a strange "place" the .410 slug is, ballistically speaking. It's easy to miss what a strange projectile it is, usually because slugs weights are measured in ounces, and who really has the ounce-to-grain conversion formula memorized. This is why my physics teachers always praised the metric system.
The loading I'm thinking of is 88 grains hurled out at 1830 feet per second. Very few handgun or shotgun projectiles are that fast, and handgun bullets, even much smaller-caliber ones, are almost always heavier. This is a projectile that is similar in velocity, though lighter and much wider, than a .30 Carbine bullet. "Wide and fast" seems like it should be very effective but, as others have said, it's not a particularly good aerodynamic shape and I suspect at moderate ranges it has lost a lot of velocity, as well as not being particularly accurate.
Those who know say the slug increases the versatility of your jackrabbit shotgun by turning into an anti-racoon slug gun at short ranges. The caliber is used in certain survival guns, so someone is probably thinking it would be good for getting meat ... but potshooting with the birdshot may be more efficient. Again, small game experts know more about this than me.