Rein wasn't quite finished there, however. He even thought ahead to Unreal Tournament 4, saying "If you think down the road, well maybe the next UT beyond this one, on Blu-ray disc, we might fill the whole damn disc with all the cool stuff the mod makers make." We'd be very excited to see that, really! So there's even more proof that not only is Blu-ray a handy asset, but it'll give us all more stuff down the line.
[Update: Changed title to more accurately reflect content.]