Yeah which ever way one wants to see it. I too want speakers disappear, only good sound is needed, the smaller the better in that sense. There is problem though, we need size to get enough bass. This is key. Even smaller mainspeakers would do if there is subwoofer system to help but if the mains is all we got I don't see we can get much smaller than this. Even this one resorts to DSP reducing lows as SPL increases, every bit of sound is reaped from the form factor.
Mind you, diffraction and other sound benefits we would want no matter the size. Size needs to be big enough for nice wide bandwidth and SPL capability. This can be achieved with good or bad sound, less or more diffraction, or any other "issues". To get more SPL with same bandwidth and quality the spekaer would need to be bigger. If less bandwidth and less SPL capability is fine, or quality compromized, then smaller speaker is fine. Its all about displacement and control, both come with physical size.