I think a good reason to publish art sooner than later, and to default to creating in public, is so your art can start accruing interest as soon as possible. (“Art” used loosely; think content & projects also).
If you make art but only ever keep it private, there is a zero chance of it ever being discovered or enjoyed. In that sense, there is some wasted potential, like cash in the mattress.
But if the art is published (not necessarily promoted), there’s a non-zero chance of it being discovered and enjoyed by other people (potentially many others) with no work on your part. That’s what I mean by interest — some potential upside, at no cost to you.
I’ve been practicing this with this very blog. I write a lot and tell no one because that feels good at the moment. However, I already did spot some interest accrued: The “Nixers” newsletter #221 included a link to a recent post where I did zero promotion. Thank you!
P.S. Another advantage is that the work is readily available to be shared if you ever choose to at any point in the future — no need to dig it up and upload it.