You could say that it is about "understanding" range, if you view range as something other than the distance at which one can hit the target. But in my experience, a deer that takes most of a tight spread of 0 or 00 at 40 yds will be more able to move under its own power than one that takes a slug at 40 yds.
Complete agreement here. 35 yards is about max for buckshot.
I've used both slugs & buckshot.
Some places I hunt you can't see further than 10 - 20 yards.
0 or 00 buckshot is ok. In more open areas I'd use slugs.
Most of my deer hunting though is done in rifle areas
of Michigan, so I use a Savage in .300 win mag loaded with 165 gr Nosler Ballistic tips,
under a simmons 44 mag scope. It's zeroed at 200 yards.