I am far from being an authority on what was done in days of yore but I do not remember ever seeing a breach scraper in any of the gun displays. The thing that I have seen is the tow worm and I believe that was the main, if not the only, cleaning attachment use back "in the day".
I have several different calibers of breach plug scrapers and occasionally, I will use one to make sure that there is no crud on my breach plug. I have never found anything. No build-up of any kind. I wouldn't say that they are a useless item because, even though I have never found any crud with them, I'm glad I have them.....just in case. But, I think they are a relatively recent development and I would be hard pressed to say that they fall into the category of an essential item. But, like I say, I'm glad I have them.......just in case.