I have killed dozens of deer with buckshot in clearcuts, but that is not why I am responding. Those particular leases, were buckshot only, so I had no choice.

Most hunters just don't know how to use it.
Actually, it can be like bird hunting.
You still have to lead the animal. Shoot where it's going, not where it's been.
I think most hunters just point and shoot like the pellets are magically going to hit the target. And they might hit it, just in the butt.
You have to know your pattern too, not just grabbing a smoothbore, and banging out some buckshot.
I use an A-5 24" cylinder smoothbore with rifled sights. It patterns 00buck better than my 28" modified 1200 Winchester.

Also, you have to know distance...fast.
Too many 40+yd, pray and spray types out there.

As far as taking two guns, if I were in a large tree-house stand, all day, I might take two guns. Overall though, its just too much to keep up with. Thats why I always chose a smoothbore for my shotgun only hunts. They are more versatile for me.
I don't plan on any 100+ yard slug shots, in the woods anyway.