I thought the same thing, but this allows you to test your changes locally as an application engineer, without the back and forth. This goes back to the good old monolith vs. microservices debate.
Writing a stable WSGI server is possible, and not very hard with a bit of attention to detail, e.g. thread counts, vacuum (just like good old php-fpm, restart every n requests...), etc. Basically if you implement most options uwsgi has, you're on the right path. It's on the roadmap to make Rwf comparable to running Gunicorn.
Sure, but Gunicorn doesn't try and run Node. I totally get benefit for development; I was just worried about someone YOLOing this into production.