The purpose of having more than one rifle comes down to redundancy and versatility. To my way of thinking, the part of the rifle most prone to failure is the scope sight and for that reason I prefer to have a second scope available or irons mounted on the rifle. A second scope is much lighter than a second rifle. Now it is possible for a rifle to suffer a broken stock through some misadventure. A horse might step on it, it might get dropped off the side of a mountain, or the hunter on a snowmobile might try to sneak between trees which are spaced to closely for the slung rifle to pass, and break off at the wrist. If the rifle is a kicker that has seen few rounds, it is possible that a recoil crack might appear during a hunt. The moose hunter traveling by canoe might tip and loose his rifle in a lake or river, and that is where a back up rifle back at camp would be a nice thing to have. If wilderness ATCs were less restrictive and easier to acquire, the redundancy issue could be simply answered.
Versatility however can usually be covered with a selection of ammunition, and a box of ammo is lighter than a second rifle. But this is where the quality of your scope comes into play. If your rifle doesn't print different loads to the same POA, the scope must have repeatable adjustments if it is to be trusted.
So while there might be some logic to having a backup in camp, for redundancy, it makes less sense for versatility. If your hunt is a fly in gig, weight is a serious issue. If your camp is at the end of a long snowmobile ride, weight is less of a concern, but room might be. The more expensive your hunt, the more restrictive weight is likely to be, but if your cabin or camp is only a couple of hours away by truck, sure take as many guns as you can manage.