I tried both versions today at the Apple Store already having made up my mind to use the Nano version after watching all the YT videos and reading this thread.
Interesting post. I was in an Apple store yesterday too, and for the same purpose, but didn't examine the screens as closely as you obviously did. Thanks.
Background: In the absence of a comparable screen on today's MacBooks, I've continued using my 2011 Unibody MacBook Pro with its optional "antiglare" display ($50-$150 extra at the time). I still prefer its matte appearance to that of the current generation of reflective or "glossy" MacBook displays.
So if I were in the market for a 13" iPad Pro (I'm not), I'd be inclined to get the nano-texture option based on this long-standing personal preference, which my hands-on time with the new iPads strongly confirmed. I just find the mirror-like reflections of the "standard" screen distracting, while the relatively muted appearance of the nano-texture screen strikes me as simply more realistic and natural.
To some of your enumerated points:
1. It didn't occur to me to check the scrolling texture of the two iPads. To me the more serious question over the screen surface might be its maintenance requirements and durability. Unfortunately, only time will reveal this.
2. This reminds me of the relationship between the perception of speaker sound quality and volume (louder almost always sounds better). Similarly, it's maybe not surprising that saturated, lollypop colors might appear "better" than more realistic ones when they're shown side by side.
4. I agree, the glare reduction is impressive.
Like you, I don't have the special circumstances or needs that the nano-texture screens are said to be designed for, but I'd certainly pay an extra $100 to have one if offered on, say, a reasonably speced iPad Air or, even better, a MacBook.