See through rings, along with the Weaver tip off mounts, came on the market in the 1950's and 60's, when ordinary hunters used nothing but iron sights and were mighty leary of those new fangled, fragile looking glass things on their rifles. The only way a great many of them would have a scope on their rifle, was if there was an immediate back up to their iron sights.
Strangely, many of those steel Weaver K2.5 and K4 scopes that were mounted on those bases, are still in use and in fine shape!