Wrong but sufficient analogy: If two balls bounce off each other in some random way and I take a look at one of them, I can tell what direction the other is going. Or if you like, by knowing the input velocities and masses, you can know the velocity of the other ball by looking at just one. The balls don't communicate, but some properties of both are "entangled".
That doesn't mean it's clear what exactly is going on and why it works, just that we're sure that relativity doesn't need crapping on for it to work.
The novelty is doing it on a GPU which means greater processing capacity, and also doing it in real-time which can be tricky with audio, partially because of latency when transferring data, but also because anything over 15ms is simply to be comfortably usable as an actual playable instrument. If you're just playing something back it's different of course, but then there's no real-time requirement in the first place.
I've made a simple and rather crude analog virtual synth running on a GPU using OpenCL, without any shared memory, that can in a pinch go down to a 1024-point buffer (in stereo) which is about 22ms, though not quite reliably. It's obviously much simple calculations, but it can easily do some thousand oscillators in stereo. The article says a 512-point buffer (11ms) is the smallest that they could make usable, which is pretty good.
I can see it being interesting in a game, different objects have different sounds and so on. Music playback is something else though. I always return to the problem of string instruments: how do you actually create the model, and more importantly the inputs? An actual violin has quite a few parameters that govern the sound. Consider the bow: pressure, angle (leaning), speed, position on the string, tension of the hairs (more tension creates slightly smaller contact area), static pressure on the strings (causing the bow and string to stick and then suddenly unsnap), exact time of contact. You'll have to either record all those from the live performance, I would guess a resolution of maybe 10 to 50ms might be good for some of the parameters, more for others. But then you can also pluck the string, and the strings and body resonate with each other, and even with nearby instruments, and you still have the whole left hand yet to be done.
It also doesn't remove the problem of imperfect speakers. Even if you separate out the instruments on their own speakers, each speaker still needs to reproduce the entire spectrum. And also, a speaker is physically a much smaller sound source than a large wooden resonator like a cello, which makes an acoustical difference.
In short, it's very cool but not a revolution. But also don't quote me on that.
Are they necessarily different? Consider, hypothetically:
"Republican in principle but holy fuck what happened with them!?"
I see your point, I too sometimes get swept up in films to the point that merely closing the player window can be a jarring experience!
Now perhaps the polished nature of film is more accessible, but I feel the the reality of theatre is just as good, even though I can clearly see the costuming and all that. It's not that they are "just" actors trying to make me believe, they are people, humans, inviting me to take part in the play. That's part of what makes it so good, the line between stage and audience starts to blur, in the way that a good standup comedian and a good audience can work together.
I think it's just a matter of what you're used to, or maybe a particular "skill" in suspending disbelief, looking past the medium and allowing the action to take place. But I don't want to sound like I'm saying that theatre-goers are better, or that one is a better form than the other, so maybe an analogy to sports works here: watching a game on TV is different from watching it in person. You can see more on TV, being there in person can be more intense. Or another one: having someone tell you a ghost story can be just as creepy as seeing it on film, or moreso, or less so. It depends on the way it's done rather than the medium
However, as for film looking more like a stage play, I don't think I would like it. I would love to see a good play of the whole Ring saga, but do I expect to watch a movie if I'm going to the cinema.
It seems that more and more mathematicians are using a new, high level language named "research student".