I believe it does, at least from the end user’s perspective. They can open a Julia REPL, access the package manager in offline mode, and import whichever packages they need. It doesn’t create a clone of the entire Julia registry, but that might not be needed.
Since new packages have to be added in installments, I would say this approach works best for a small number of distinct teams, which is probably the norm on air-gapped systems. Each team would probably use similar packages and could have a designated sysimage. It would be a poor fit for, say, a university of students who each want to try out various packages in the Julia ecosystem, and that’s where I think an actual clone of the registry would shine. But maintaining that would still involve periodic updates.