Generally speaking, the Z lenses have been notable optical improvements (compared to the f-mount lenses). And this lens isn't really in that direction. So those that want it are buying it specifically for its size and maybe for its cost--but not really for the optics.
In the Ricci video linked above, he says that "the image quality is incredible," and better than the 28mm f/2.8. So why do you think no one would buy it for the optics?
Yeah...purple fringing in the highlights, no special coatings so flare seems to be a thing. You can see this in the first sample show he shows. (Also, worse bokeh than the 28.) His basic take is that it's better than the 28. Well, ok...it's also priced at almost twice as much. It had better be better.
No I haven't seen MTFs for it, but it seems pretty clear there are better options if optical quality is the main goal. Obviously those optical improvements come at several costs, which aren't nothing--size, weight, cost, etc.
I'm not dissing the lens. It doesn't have to be "bad." But optics aren't going to be the primary driver of its purchase. Cost maybe, size absolutely. And maybe a cost/optics ratio that works for some people. And that's fine. But that probably also explains why no one is bending over backwards to put out a review--you already know the two most important selling points. If you're intrigued by the lens, the optics wasn't the intrigue. And that's kind of the only thing a review can provide new info on.