I grew up in the shotgun zone of MN and moved to rifle zone. I was always told by the old timers that tue reason for the shotgun zone was that shotgun slugs won’t travel as far as a rifle bullet. Most urban and agricultural down there. I get the idea and I couldn’t hit the broadside of a barn with my shotgun so maybe they were right.

actually couldn’t hit a paper plate at 100yds with a rifled barrel and sabots.
I was 20 years younger then but I still remember the sound of slugs zinging through and hitting the tree limbs above my head. The slug will keep going if you shoot high enough.
I believe rifles are superior to shotguns and would hope hunters hit percentage would increase if straight walls were allowed because rifles are more accurate, easier to handle, less recoil and rifled.
I won’t be going back to the shotgun zone unless they either allow straight walls or change it to muzzleloader/single shot only. Which is unfortunate because there are more deer down there. Too many poor shots that shot till empty down there.
I do recognize that a poor shot with a shotgun could still be a poor shot with a rifle. But at least the rifle is taking some of the error out of the shot.
Straight walls are a benefit to those who hunt shotgun zones and want to use them and aren’t hurting those who aren’t required.