A key thing they do is offer finer-grained roles[1] for project and team (i.e. subteams within an org) management.
You're right that they don't provide namespaces, yet. I believe there's ongoing discussion about how to enable that, including via PEP 752 and 755.
[1]: https://docs.pypi.org/organization-accounts/roles-entities/
I can also say from direct experience that (1) it doesn't get very much funding, and (2) they take plenty of external suggestions and contributions.
However, later in the thread there are updates that look a little better.