Ahh see, that's the beauty of BSS. When done correctly you don't have to scroll much for anything. Search works great, and when you're working on a component, all of the classes and ID's that are in the component show in the Styles main window so if it is not there, that means it's not connected to that component. If it is there, then it is connected. If you have a class on your component, but it's not showing up in the Styles window and should be, then most likely you altered the name of the class in the file or in the component and you just need to do a search in the file it is in. If you have it all in the same file, that means you don't have to open multiple CSS files to find things, it's all right there, just search for that class name and if it's there you can check to see why it's not connected (which is most likely a name difference between the file and the component).
BSS gives you a very easy way of updating your classes that are connected to a component without having to search for them no matter what file they are in, because they are all right there at your fingertips. This would be the same no matter how many CSS files you used, so the separation would actually be a useless setup for using BSS. I could see if you were doing hand coding without a visual interface like BSS, (even then it's still not efficient or speedy for your visitors), but with BSS it would be a wasted amount of time as you'd never see that difference in the app. The only place you'd see it is in the grey name of the file to the right of each class. Need to get to that class specifically within a specific CSS file? just click that grey file name and it opens that CSS page. This isn't needed very often if you follow simple procedures like:
In the styles window all Media Queries go from bottom to top same as responsive design goes smallest to largest. This means the main class is at the bottom and if you add a media query you would duplicate the class and add the media query to the one above not the one below. This shows opposite in the CSS files themselves, but in the app that is what gave me the most headaches at first lol. I just couldn't figure out what it was doing, and I'd get them wrong all the time and have to open the CSS file and fix it and I finally realized it was doing them opposite to how they end up in the actual CSS files. That will help keep you from having to scroll the actual CSS files much at all.
Prepending classes or using ID's is the proper way to do it. Every added CSS file adds time to how long it takes for your pages to load. But then as I mentioned, i don't adhere to all the rules myself either just because I'm stubborn haha. I don't minimize because it's just added work after every export that I don't want to mess with and the internal minimizer doesn't play nice with 3rd party components and such either so I gave up on that idea. Maybe someday, but not right now. I also have multiple CSS files for multiple components as well. I use 3rd party menu systems, gallery setups and a few others and I don't combine those into my main CSS. Some people do, but I don't as I don't want to break things and that usually does break some things.
In the end, you are better to get used to the more proper way of coding (even when hand coding things should be done mostly in one file rather than separate ones, and for sure you don't separate files for the main components of the pages, especially if it's components that are on all the pages and maybe just a different image background or background color etc. For instance, I have a site I'm working on right now that has a different background image for every main category header area of the page. Lots of dropdown items in their menu and they wanted each category to have a different image so we did that. I just named the classes with added numbers so I could keep track of which was which for adding new pages. Simple to do and as I said, it won't matter in BSS, you won't know you went through all that work of separating things because it will show up the same in the Styles window no matter how you do it.
Hope that helps.