I'm working on an open-core product [0] right now, and an aspect I find missing in the article is that you can generate trust by showing how the internals work. This is especially beneficial if you work in an area like us. Of course, you need to make sure your license is set right and you need to think about where new features go, but it's a valid use-case.

[0] https://pirsch.io/ open-source core: https://github.com/pirsch-analytics/pirsch