They did change the wording on that dialogue lately, and it has recently asked for the BB location and from there the installer finds the realtracks folder (in BB)
So it does get installed to the realtracks folder, but now the installer takes the extra step to make the install smoother for users.
I think it even states it's usually the BB folder.

You probably remember earlier versions where finding the realtracks folder was the burden of the user. That long folder list in BB would open up, then you'd have to scroll down to the 'R's etc.. new one is quicker, just pay attention to the drive being used. External and internal should be updated, so the backup has the updates installed too.

I do not work here, but the benefits are still awesome
Make your sound your own!