As I've mentioned on other threads, I'm now at a point where accurate shooting with iron sights only happens on days of good lighting conditions combined with days when my old eyes are at their best. Unfortunately, with our climate and my old eyes, those days are getting fewer every year. No way I'm I going to let my lever guns sit around till I get such days, especially out of some false notion that only iron sights are proper on a lever gun. As Sir Henry notes, scopes have been around even longer than lever guns. Let's face it, much of what we regard as traditional western guns and the way they were setup and used is a little less than historically factual.
I don't like big scopes on my lever guns, mostly because of the way they change the handling and balance, but, then, I don't need such scopes on my lever guns, either. I've shot some very nice groups at 100 yards with 30-30s equipped with nothing more than a vintage 4x scope. A 1-4x or 2-7x class scope does everything I need to do at the distances I shoot my lever guns.
As for looks, I see nothing ungainly or out of proportion with this little Leupold 1-4x on my Marlin 357. It's small enough and light enough that I hardly know it's there. Make no mistake, though, even with this low power, I shoot this gun better with a scope than a peep on ANY day and I have the groups to prove it.
Again, nothing against those who don't want to scope or even go red dot with their lever guns. I get that. I like iron sights, too. I use them when I can or when I'm in the mood. Not about to abandon scopes, though, based on some erroneous and unfounded sense of what is or is not traditionally correct. I'll shut up, now.