> "Be Nice" may dissuade commenters/potential customers from pointing out legitimate, immediate flaws.
I don't think HN users are going to have trouble doing that, but there are different ways to do it, and the nicer ways have the critical property of opening the discussion further instead of shutting it down.
We HN users are used to thinking of ourselves as the scrappy underdog, calling out incorrectness and badness with pristine honesty and with no particular effect on the situation, except occasionally a righteous one like forcing Google to do customer service. We don't think of ourselves as being in a position of power, but that's actually an illusion, as many who've walked into a wasps' nest of critical comments and come out stung can attest.
To me one interesting social aspect of this experiment, quite separate from who gets funded, is that it unambiguously puts the HN community in a position of power—a perspective that we're not accustomed to, and which requires developing different habits (edit: I mean a higher standard of conduct). Maybe those habits will end up translating to the community as a whole (yay!) Or maybe they won't show up at all (boo!)—but at least we can all keep reminding each other to be nicer in these threads.