Sorry, I had definitely misunderstood the public/private namespace distinction, since the definitions in the PEP are not what I expected those words to mean (the “open/closed” labels some folks have mentioned feel more intuitive to me). I believe I understand now, thank you.
IIUC, really the only thing public namespaces get is a visual indicator on ‘official’ packages (and in metadata), not any real significance to the names or namespaces themselves. In that case, I think this is a small positive impact for projects like Jupyter (visual indicators are nice), but since only private namespaces appear to address typosquatting, dependency confusion, etc., I’m not sure Jupyter adopting a public namespace would have any real impact on users. The main real user pattern I see being affected for public namespaces is pypi.org search (which I definitely use!).
It might be worth addressing this significant difference in Public/Private scope in the Motivation (or Public Namespaces section) because I don’t really see the goals in the motivation as addressed by public namespaces, and I started with the incorrect impression that Jupyter might have the benefits laid out in Motivation (typo squatting, dependency confusion), when it really won’t.
For Public namespaces, I might also suggest adding to User Interface a visual indicator that a package that is in a namespace but not official. It’s hard to make a decision on the absence of information in UI, so if someone visited a tyop-squatted package within a Public namespace, there is no indication that it’s not official, only an absence of official indicator, which I suspect most folks wouldn’t know to look for.