As far as I know, yes. However, I don't think that the fonts that are loaded in the sbfonts directory are visible to other Windows applications.
I think you are right. But, what you can do is just open the font in the sbfonts directory & minimize to the desktop & it can be used in other programs.
You can do this for any font you have in any folder on your computer & it will work in other programs.
That is why you dont have to install the font into your windows fonts folder. Although some of us get a little crazy with it anyway. I have over 900 installed, absolutely no reason for doing it either, just a fontaholic.