Shotgun slugs are good for hunting medium to large game at short ranges by firing a single large projectile rather than a large number of smaller ones.
In many populated areas, hunters are restricted to shotguns even for medium to large game, such as deer and elk, due to concerns about the range of modern rifle bullets.
The big advantage of using a slug is that it has a much longer effective range than buckshot.
A 50-75-yard shot on a deer is usually well within the performance capability of a shotgun shooting slugs.
To be most effective, the sabot needs to drop from the slug as soon as possible after leaving the barrel, much like a birdshot wad.
Shotgun slugs came out of the dark ages with the advent of the sabot slug and rifled shotgun barrels.
It is a common misconception that shotgun ammunition is a good way to chase away a bear. In reality, target or bird-hunting shot is an ineffective solution that often leads to unnecessary outcomes.
Bears have relatively thin skin and shotgun ammunition can be extremely harmful and even lethal.
Buckshot is better for home defense because the intruder will be in the house and at close range in most cases.
Since buckshot disperses tiny pellets when fired, you have a better chance of hitting the target, even in the dark.