what are the practical benefits of namespaces that you don't get with

username_logger, username_fuse, etc.

?

A lot of the supposed benefits seem like downsides. The ability to have

bob_ward/docker and lilly_smith/docker seems like a misfeature

I guess you could argue it makes to avoid malicious packages w/ similar spelling but then they could just try the same thing with even less suspicion w/ similarly named namespaces