No it doesn't prove your point at all, I bought mine because I purely wanted the stainless components (kettle, elements and malt pipe). I actually asked KL to sell me a dumb version sans controller but sadly they said no. I wouldn't have bought any of the other 1V systems in the market because they don't suit my needs either modified or off the shelf.
I modified mine as soon as they appeared in my brewery based on my own engineering principles and because I already have a superior brewery control system than 'RAPT' and better pumps (including true pwm speed control), not due to performance of the system. As I did with earlier Gen3.somethings and digiboil vessels. The biggest differentiator is the centre drain, which although far from perfect in the BZ implementation is still far better for CIP than a flat vessel with pickup tube like comparable systems.
What does dead space gain you - genuine question cos I can't think of a benefit myself? I use these vessels as the basis of my own bespoke brewery largely because they do have very little deadspace relative to standalone dished kettles like the cheeky peak ones.
If there were designed off the shelf with the extension built in then yeah they'd be be too tall and narrow for new brewers, but as they are they're fine, surely. If you can't dial back the flow slightly (not that I've had to myself) to deal with a slower recirc well that's not really the problem of the brewery.
Which single vessel systems have better geometry, and why is it better? The perforated bottoms of the malt pipes, although I haven't bothered to measure cos I've never felt the need, visually look identical to previous versions of the BrewZilla/Robobrew and standalone false bottoms that I've seen and owned in terms of hole size and spacing. The height and radius of the vessels also seem to be comparable to other 1V systems. I'm far from a KL fanboi but I'm genuinely baffled how the BrewZilla would perform any worse than a Guten or Grainfather or any other comparable system as a recirculating vessel. Disclaimer: completely ignoring the RAPT control system because I haven't used it and don't want to. If your argument is based on RAPT issues then go your hardest.