Indie Projects with Open Source Code

I'm curious what the thought process is for companies who open-source their code. I've seen a number of companies doing this from Discourse to MonicaHQ to Plausible.

Most of these services would cost more to host yourself than to use the company's hosting. It makes sense that even technical people would take that option to avoid the extra expense and extra work with hosting it themselves.

A few thoughts:

Pros:

• Pull Requests
• Engagement from developer-centric communities
• If the project fails, the repo can act as a resume.

Cons:

• Bugs could be exploited before you could get them patched (or even notice they exist).
• Someone who is better at marketing could take your code and "steal" your user base.
• You're less likely to get acquired.

If you've open-sourced your code, how did you make that decision?

If you have a closed source code base, why did you make that decision?