In really large projects (e.g. SciPy as mentioned in the article), lazy imports make sense. Especially with the popularity of decorators, importing a file without any apparent module-level code will actually need to run a nontrivial amount of code. Multiply that by a few thousand files in a library with a tree of "import * from ..." and you're looking at perhaps seconds of startup time. Lazy importing can short-circuit that, but still make symbols available for ease of use.
