You make a good case for not using nightlies, except that you haven’t addressed the reason why people DO use nightlies - that they are much more up-to-date than the most recent Beta release.
It’s clear from recent postings that a lot of non-Devs ARE using nightlies, and you have earlier said that they aren’t too time-consuming to produce.
So what do you think? Would it be unfair, or would it be counter-productive, to ask for quarterly or even four-monthly releases?
Is there any way in which non-devs could help?
Because I think more frequent releases would be useful in a number of ways. It’ll look good; it’ll lead to a better experiences for newbies; it might help to encourage/focus the development team; and you could even hide the nightlies completely except from the developer team.