Social support dependent on trying to be "useful" requires a social consensus about what qualifies as "useful;" I don't think this is an agreement we can come to, as all creative work, especially (but not only) artistic, scientific, and novel entrepreneurial work, tends to be non-linear in terms of return, highly dependent on chance, and opaque in terms of future utility. Non-euclidian geometry was not considered a "useful" branch of mathematics for centuries, until Einstein came along and used it to formulate his theories about space-time. Worse, imposing a "usefulness" requirement gives quite a lot of power to the bureaucrats tasked with drawing the line between "useful" (that is to say, subsidized) labor and "useless" labor. A society that can afford to provide a basic level of subsistence without strings attached should provide it with no strings attached. Only in this way can the full potential of human creativity be unlocked. Let the generations that come after us sort out "useless" and "useful." It is foolish to pretend we can divine as much as we do.
Focusing on material end results over process and relations contributes to the dehumanization of us all. Mindless consumption contributes to this pathology. The discourse over art and generative AI provides a clear, beautiful illustration of this. If art is just wallpaper and not a form of communication, a real insight into a real person, then artists don't matter at all. On the other side, if all you care about is the end result of creation and not the way in which the process of creation changes you, then why bother creating anything at all yourself? Removing the human results in us being effectively little better than cogs in a machine, and will result in us being treated as little better than cogs as well. This is one of the most basic elements of anti-capitalist thought.