It is easy to ship any proof of concept. Is it hard to maintain, it is rigged with performance issues and it is almost impossible to refactor because python has zero refactoring support and no compiler to help you catch any error.
What you save on the initial rollout, you loose ten folds on the long term.
https://swreflections.blogspot.com/2013/09/this-is-how-faceb...
This just makes me shudder a little bit. I've seen such things before, even recently at my current job. These kinds of applications tend to be a nightmarish mix of unmaintainably overengineered and underdesigned terrible code.
The key thing is that the testing, release and deployment tooling were not a significant bottleneck. You could develop the code, perform testing in a production like environment and sign it off with a minimum of down time in between waiting for compilation, package building, etc. So a lot of that was down to Python being interpreted.
We were sometimes able to go from concept to deployed application in a single day.