Summary

Documentation can help greatly in a project's popularity and bad documentation can kill productivity. I think there are few aspects of a library that have more impact on the usage by third parties than documentation. Thus in many cases, documentation is a more important factor in deciding the usage of a project than the actual code quality. That's why it is very important to always try to have some documentation available.

With Sphinx it is actually easy to generate documentation. With just a few minutes of your time, you can have a fully functioning website with documentation available, or a PDF, or ePub, or one of the many other output formats. There really is no excuse for having no documentation anymore. And even if you don't use the documentation that much yourself, offering type hints to your editor can help a lot in productivity as well. Making your editor smarter should always help in productivity. I for one have added type hints to several projects simply...