I think you are taking someone's opinion very personally.
It's also been my experience that with many aficionados of these kinds of instruments, realism is paramount up to the point where it suddenly becomes about "expressiveness", which is of course an argument that can't be won - if you find something expressive to you, you will always be right in saying that it's expressive to you. But it's not just realism I'm looking at - it's tepid vs. solid intent. And if I'm going by sound alone, I don't find the depicted example compelling, though I know it was fun to do for the player.
I don't want people to stop working at this for any reason - I love modeled instruments and I'm fascinated by alternative input devices. And I've been impressed for example by some of the folks in India playing GeoShred versions of Indian instruments, the performances of which are full of beauty and mastery, and one would think Geoshred would be far more of a blunt instrument than the Roli, so that's a testament to the player's ability. But in many cases of what ends up on YouTube showing off Roli controllers - or even GeoShred or Linnstrument, for that matter - I'm hearing folks in the rosy stage of infatuation with how it's much more freeing than a conventional keyboard, but apparently it has also freed people into cramming every moment with lots of expressiveness, or has them enjoying the sensation of emoting with a finger so much that the sound produced is somewhat secondary. It's easy to be swayed by this - I recall when my partners and I got a massive new screen for the studio and after watching cues we'd done, someone saying, "is it just me or do our cues sound better?" It's related to how some people make elaborate facial expressions or lean their bodies into holding a single note on a plastic keyboard - there's nothing wrong with it per se and people should be free to do that or anything, but the effect achieved musically isn't the same as the one achieved in the player's mind. I like the idea of MPE and am all for it - but what is to be gained from it by a player who hasn't the ability to own that way of playing? Keyboard players are often accustomed to instruments doing things for them, and the new generation of controllers and instruments demand more than many are prepared to give.
But that's just a stranger on the internet talking. If you are satisfied with this as an example of how it should be done, there's no problem, right?
I think you're conflating some of the marketing hype about the realism of physical modeling VI like SWAM and Pianoteq (including overblown Youtube clickbait) with the purpose of MPE controllers. The primary point of instruments like the Seaboard, Continuum, and Osmose has always been expressivity, not "realism".
As I've posted many times in this and other threads, I personally prefer physical modeling VI that don't try to be "realistic". I prefer the timbres of Friktion and Modelonia over SWAM and Pianoteq. As I wrote recently in one of the Pianoteq threads, even the latest Pianoteq update still lacks the timbral complexity of sampled instruments (the physical models are oversimplified, and sound like it when you listen closely), which is why I find the timbres of SWAM and Pianoteq less appealing. Physical modeling technology now and for the foreseeable future probably isn't going to have enough computational power on a home computer to simulate all the complexities of an acoustic instrument that humans can hear (though the example of Synthesizer V makes me think that neural networks---or perhaps "physics assisted neural networks"---may succeed in the near future where pure physical modeling has not). Of course, drenching them in reverb (or other effects) helps a lot, and can certainly produce results that most people would not be able to distinguish from the instruments being modeled. That's what Parisi does with SWAM strings (for at least one piece featured in a major Hollywood movie soundtrack, among other things...).
Perhaps the combination of a simplified model of the basic physics combined with heavy reverb explains Physical Audio's preference for "ghostly" timbres---which current physical modeling technology is well-suited towards. OTOH Physical Audio also demonstrates how going beyond emulations of preexisting instruments can add timbral richness through different kinds of complexity---mass-spring networks, networks of resonating plates and strings, etc.
Friktion, Modelonia, and Plasmonic are good examples of how physical modeling timbres can be made to sound rich and complex, though at the expense of not sounding as much like a realistic emulation of an acoustic instrument.
Still, I'd love a PM virtual instrument based around (or inspired by) the expressivity of bowing action with a timbre like Friktion but the expressively playable vibrato of SWAM strings (as well as a wider range of timbres, and more experimental options).
As for the learning curve for instruments like the Seaboard or Osmose... it takes a lot less time than learning to play the violin
and cello and flute and... all the other possible instruments. And for about the last 7 years I've generally been using the Seaboard as my only instrument aside from my voice.