Yes, for a person that takes care of the rifle and does not throw it around gun racks and beats it up in the outback, sure, the side mount rear sights are OK. I put a couple of rifles together many years ago for a rough and burley guy, he wanted a drop proof rear sight: One that would survive a upside down drop to the rocks. So I came up with a none adjustable ghost ring style machined out of solid 4140. Took a few tries to "regulate" the rear sights, but end result was point of impact at 50 yards, which he wanted.

My 375 has a Lyman 48 on the rear bridge, I bent it years ago when I fell down a rocky slope. The rifle was useless until I had it back in the shop, put in another slide and aperture, and sighted the rifle in at the range. It was a good thing I was elk hunting in the local mountains instead of on some far away hunt!

So, my opinion, and you know what it is worth, is if a rifle receives reasonable care, the normal receiver sights are just fine. But if a rifle is subject to rough use and must be the utmost in reliability, over and over again, in and out of vehicles, drug through countless miles of rough country,then a fail safe system should be employed. I feel that a big bore "stopping class" rifle is intended for use far, far away from a gun repair shop, so it should be iron clad.