Still, keep your new 10.6 disc. If your hard drive fries and your backup doesn't work for some reason you will have to reinstall from scratch and you'll need the 10.6 installer disc because your computer likely won't internet boot to Mavericks the way modern computers will.
By the way, marketing idea works both ways. Several years ago radio stopped working with my iTunes version, and so did Apple Store. So, I disabled radio completely on iTunes and work directly with URLs in VLC and use browser streams. I guess for the radio stream service it probably doesn't matter to Apple since I don't think they make any money from providing a list of streaming servers (the real cash cow for "free" iTunes is the media store). As for iTunes Store I can't get access to it with the result Apple makes no media sales to me.