I wasn't aware that Python3 was pre-installed on major distros, I don't believe it was by default on my Ubuntu 16.04. It is possibly I removed it, though. It does look like 18.04 is going to bundle Python 3 [1]. I agree with you that adding JVM is an expensive decision and the runtime requirements can make using them in real projects a big pain.
Thanks for the video, I'll check it out. It is exciting (and I would also say a bit worrying) to see a lot of competing tools in this area.