I exclusively use a peep on all my muzzleloaders. I also use globe front sights.
In very low light in timber. Most of my shots have been very close. In those cases. I don't worry about seeing the front sight. My eye centers the rear sight. The globe is centered in the peep. I focus my eye on the spot I want to hit and let my eye center that spot in the globe. The last deer I shot this way. I shot in the neck at about 40 yards.
Where my peep sights really shine is out in the open terrain of the desert.
Use a range finder, set the sight for the distance.
The open sight shooter is aiming under or over, which is a horrible way to shoot game.
My son shot this larger buck just before dark. He settled his fine pin in the center of the Bucks white patch in its neck. He shot the buck at 175 yards. It was dark in no time.
Knowing your rifle. Knowing your sights, and practicing in the areas you hunt help make the peep sight really the best option.