PM, I shot a smooth barreled, scratched up, canoe paddle of a moss berg pump for yrs. Like you it was all I needed, just change up the ammo for the game your hunting. It had a rib along the top of barrel, made a big difference. I also shot rifled slugs for deer. After many years of hunting and bench shooting, a smooth barreled SG shooting R slugs works just fine, depending on the range you want to hunt. Most my deer have been taken under 50yrd's, usually much less.
I found with a S.B gun with R slugs, you won't group shot's 3 on 3 at the range, but good enough to use to harvest some meat at the 50yrd or so range.
A few yrs back someone decided they needed my beat down old moss berg more than me, along with the TV's and wife's jewelry, another post for another day? Miss that gun, lota yrs with it. Replaced it with a Remington combo with a smooth barrel and a rifled slug barrel, scoped. Shooting sabot slug's with the rifled barrel and scope, can group 3 inch at 80-100 yrds.
Think alot depend's on your hunting preference/range, we hunt powder, shot gun every other yr. With the scoped SG, still shoot my deer under 40 yrds. Ammo is exspencive as well. They both work well, one last consideration is your age vrs eyesight, once past 50 (yrs old ), scope will take back a few yrs??