You can actually be bothered encoding the originals to divx? If you have the originals, downloading would probably be quicker hehe. Wonder what the stupid MPAA would have to say about that? Idiots... oops sorry I'm heading off track a bit!
Back on topic:
Yes it's worth it, but what if they are kids, which yes they are, they will rape discs easily. And if you get scratches on RW (even small ones make a difference) it makes it very unreliable to read and burn multiple times.
You are better off using the cheapest SL media that will work fine. You don't even care about longevity do you? Ritek G05 might actually be a good option for you! Haha, they are cheap as hell but naturally degrade and die by themselves after about 6 months or so. They do burn well initially and work great, but it goes downhill from there. But for a cheap price and for absolute throwaway discs, why not just use something like that.
Bottom line: I say no to RW, not as compatible after many writes and also sensitive to scratches.