ROFL at Vern's post.
Scopes can be affected by dust, rain, sun reflection and eye relief. Also when you throw up a scope at it takes the brain a spilt second to go from normal 1 times vision to even a small magnification factor. And finally no matter how small the magnification is on your scope, when you look through a scope at an elephant at touching range you can't see the whole animal in your field of vision.
Well, not that I'm ever going to Africa or Alaska for hunting. I mean, I can barely afford gas to get down to my place to hunt deer.
But I find it faster to not have to search for a front sight in a rear notch and focus on target/front sight even with good eyes like I once had. LOL I do like a ghost ring aperture type sight, have that on a lever gun in .357 magnum and it works really well. The front sight sort of centers itself, unlike trying to use an open sight.
I've seen elephants at the zoo, before.
But, if I were going to actually HUNT one, perhaps an aperture would be the way to go on those things. Your points seem sound. I'm sure the field of view is sorta filled by one of those things even on 1.5 x.
I do have a set of Millet "scope toppers", think they're called, on my .308. What they are, are iron sights atop the scope rings for last ditch use if the scope is fogged from wet/cold weather or breath or something and back up if I were to drop the rifle. The sight radius is awfully short, but I can hit at 100 yards with 'em fairly well and a big animal at close range wouldn't be hard at all. The big trade off with 'em is you have to lift your cheek weld off the stock to see 'em. But, I got 'em to put on a Contender and wound up not using 'em, so I stuck 'em on the .308. Figured they MIGHT be useful someday, never know, and no use lettin' 'em sit on a shelf.