Well the blu-ray is meant to be a multi-audio track lossless version of the album. It's 22 GB in size and they typically don't offer a watered-down version of it. That's what the CD is for, though in this case you are right seeing as the BR is yet a different version of the album you'd want a ripped version of it.
I'd say the BD would be meant for visual enjoyment only if they only included the 5.1 surround sound mix, but they also included a down mixed stereo version of the Ultimate Edition Mix as well, so it seems odd that they could not just offer that as a digital download for folks, especially those who bought the BD and don't have any way of ripping the audio.
As for my version, I got the FLAC files from a fellow member here and then converted them to WAVs, used Audacity to tweak the track indexing a bit (as the raw audio tracks started each song just slightly before the downbeat of each new song, which annoys the hell out of me), and then I reconverted those WAVs into MP3s, which now reside on my phone, right under Forevermore and The Breath Of Life.
Personally, it really is the best of both worlds, more or less, though even if I wanted to take something from either Forevermore or TBOL and put it into my Ultimate Edition Mix, it would take a bit of audio level editing as the stereo mix of the Ultimate Edition is a bit quieter, maybe more dynamic, than either of the two CD versions of the album.
You can see how the WAV files compare in terms of audio peaks here in my Audacity comparison of the Overtures:
And here's one of how the 3 versions of "The Greatest Story Never Ends" compare:
The BD's visualizer that accompanies the audio is a trippy journey with some fantastic artwork and animations, definitely worth viewing. Whenever they actually get to play the album live, I'm almost sure these animations will be used as their back screen projections.
-Marc.