I think this point is a major difference between those who use compression and those that don't. I use FLAC for music because it's the better archival method vs. MP3, even if I can't distinguish the difference in quality between FLAC and a 256 MP3. With FLAC I can always easily convert it to another lossless format (e.g. APE, AIFF, etc.) or even a lossy format. Converting from MP3 to another lossy format is not wise.
I feel the same way about movies. If I have the ISO, it's the closest to what's on the disc. I can always use compression later, but I want to start with an archival-quality digital copy, at least for long-term storage. If it's for ripping movies for the kids to watch that will get deleted when they get tired of watching it, maybe not so important.
I do end up with a rip of the main movie, lossless audio and any forced subs, but it is all bit-for-bit identical to the BD. Other than losing all the extras and the crap they try to force us to watch, I never considered "losing" data from the movie itself. I'd guess that most people with a dedicated home theater (BIG screen and proper surround config) would take the same path. If someone starts out looking at compression for their streaming/achiving, then likely they had some concerns about storage going in and/or their usage is such that the 1080/24p and lossless surround on the BD isn't important.
Hey Jeff! I sometimes lurk in this thread but have rarely, if ever, posted in it.
Isn’t the issue how efficient the compression algorithm is? The BD content is already compressed but they use a fairly old (by computing standards) technology. This means that the movie compresses down to a fairly large size. But AIUI there are now far more modern and efficient compression algorithms available which can take the content and further compress it without any additional loss of information. The result is a much smaller file for 'archiving' but no visible degradation of PQ when compared with the original BD.
It's much like using the ancient ARC compressor on a document file as compared with a more efficient compressor such as ZIP - the content is identical in both cases but one results in a significantly smaller file size.