While in modern music I do not remember songs with impressive stereo effects, most of the albums that I was listening when I was young, both rock music albums and classical music albums, were severely degraded when listened in mono.
Name an example, and name the effect that was significant enough to the upshot of the song that mixing the stereo channels down to a single mono channel would lose prime information for the listener.
I'm not saying there aren't examples, but I want to listen directly to an example you would consider severely degraded if heard in mono (i.e., stereo channels mixed down to mono and then just copied to two channels).
I was going to say Sgt Pepper's Lonely Hearts Club Band - title track and Within You Without You. But it turns out they want you to listen in mono anyway!
Going further with another Beatles tune-- listen to the mono mix of "Helter Skelter" and tell me what in the first 10 seconds clues you in to the fact that a) it was recorded in 1968 and b) that it's even in mono! And don't cheat by comparing it to the stereo version.
In any case-- compare that experience to video recording/playback quality. I can't even show digital videos recorded in, say, 2004, to a young audience because the general quality is already considered complete crap. My own confirmation bias can't even fill in the rift. Standard DV stuff from that era-- even if it's something I care deeply about-- simply looks blurry to me now.
The funny thing to me is that silicon valley still markets improvements in audio fidelity/spatialization as if they are the same qualitative jumps in quality as video improvements. Ok, I get it that VR probably necessitates sounds emanating from behind your head. Fine. But generally speaking there is a ton of hype around audio that simply isn't warranted, at least for a consumer or even prosumer audience. It's not blockchain-level hype, but still...
