It may not be a good model for "a coherent real-world theory of economics or government", but it sure is a good ideal to strive for. Sure it's utopian compared to what we know from history, but then again, it's not much more than what a sane group of adult individuals behaves like on a good day, except generalized to the level of planetary government.
Personally, I like to have this ideal that tells me people can get better every day, that we can make the world brighter for the future generation than we found it ourselves - than to keep looking at the real past and use its worst parts to excuse and justify perpetuation of wrong or evil behaviour. The latter is exactly what we're doing when we're saying "UBI smells too much like Soviet Union, so let's keep people working increasingly pointless jobs, hoping the Market will solve things before they all blow up in our faces".
I'm not sure that a concept drawn from explicitly utopian science fiction, whose creator also believed (for example) that workplace interpersonal conflict would cease to exist some time in the next three or four hundred years, is the best principle on which to attempt to develop a coherent real-world theory of economics or government.