This is purely my opinion. I see 70mm as mostly a movie scam to extort exorbitant amounts of cash from a ticket for something that's vaguely noticeable outside the aspect ratio itself. Note that I'm not disputing that there is a visual difference, there is, the image is clearer, shaper, with better darks, but the entry fee paired with how out of the way 70mm is, it's just ends up feeling like FOMO. My opinion doesn't…
However, these discussions always feel similar to MP3 192kbit/s vs AAC 256kbit/s vs lossless vs lossless 24-bit 192KHz. Trained listeners can hear the difference between MP3 192kbit and AAC 256 kbit. Perhaps even AAC 256kbit vs lossless. But IRL it does not matter:
- Some people listen on very crappy headphones/speakers.
- Some people listen on good headphones with AAC, but even with AAC on, external sound leakage probably has a larger effect on the perceived signal than compression artifacts of AAC 256kbit/s.
- Most of the time people listen to music in the background, so there is not a lot of attention on it anyway.
- Many (most?) people primarily listen to melody and lyrics and not to the fine grained details of how the instruments sound.
Similarly, a lot of people who watch movies, as long as the image/audio quality is good enough, they focus on the storyline, the dialogs, the general atmosphere, etc.
I am not denying that there is a market for audiophile audio or the best quality image for movie visuals buffs, but for most people these are just overpriced gimmicks. I mean, we used to watch movies at home on crappy, small CRT TVs, and many of us still have fond memories of many movies despite seeing it in a format that could as well be from the stone age compared to even a standard projector used in an average cinema nowadays.
To avoid any straw manning: I am certainly in favor of all the improvements in tech we have seen, it's more that the experience does not linearly with it. More like exponential saturation.