I have never cared for cheek rests on a shotgun. It is my belief that, even on a rifle, they are there mostly for aesthetics. They perform no basic function that cannot be achieved with a properly designed buttstock which does NOT have a cheek rest. In his great book, Stock Fitter's Bible, Rollin Oswald goes into great detail explaining why each part and dimension of a shotgun's stock is important. Nowhere have I found that he gives shotgun stocks with cheek rests even a casual mention, which is telling.
However, if one really likes that style of buttstock with a cheek rest it certainly cannot hinder anything in the way of good shooting, as long as the stock with it fits the shooter properly. Having shouldered several shotguns with cheek rests in my lifetime I've never found one that felt right for me. And, if I cannot mount the gun with my eyes closed, getting a good cheek contact with head upright, then open my eyes and find I am looking right down the rib, I will not be able to shoot it well.
In America the cheek rest has it's origins in the muzzleloading rifles of the 1700-1800 era. They were often built with a crescent shaped buttplate which was not intended to be fired from the shoulder pocket as we do with modern guns today, but the buttplate was intended to be placed just outside the shoulder joint, almost on the upper arm itself. This required more wood to be left on the cheek side of the buttstock to give cheek support for good, and steady aiming. I competed for many years in NMLRA patched roundball competitions at the state and national level, and I can assure you that every successful offhand rifle shooter used that stance and mount when shooting m/l rifles with a hooked buttplate. THAT is the reason it was commonplace in early America. The sideways stance required to shoot a m/l rifle this way also gave a battlefield advantage, a narrower target for the enemy. Pistol duelists on the frontier adopted this sideways stance for the same reason.
