I love shotgun cards on both the receiver and the stock and in mag pouches, but any pouch with loose shells is a BIG additional plus to me.
Any human with moderate dexterity can and will flip a shell work wise without thinking before it comes from the pouch to the loading point. With very little practice.
So I say both/all. One immediate, one if the 1st option is dry.
This has bagged me a few farther out running coyotes over the years and I won't be without the option.
The thing about real use shotguns is there may need to be a variety of ammo on hand to select from ie hard slugs, buckshot, "current best coyote shot", birdshot for the big snake in the yard. Options that let you tote that variety are always a good thing.
So, cards.... and a pouch, multiple ammo options, is where I fall on the "get up in the night with a 12 ga. because my dog is aggitated". Skunk, javelina, mountain lion wanting to kill my dogs, feeding mule deer, bobcat, neighbors Bull, neighbors steers or cows just moseying around, kids pretending to be big city gangbangers, kids being legit heroin selling gangbangers, with a light I'm good for all of those.
Extra shotgun ammo on the belt along with a pistol, ammo, handheld light, fixed blade. It's not that hard or expensive to be able to deal with a wide range of threats in the dark.