We have gone way off topic here but since we are talking about convincing people to choose Lua instead of Python for an embedded language, here are some arguments that worked for me.
- Security is a good one. Lua is much, much easier to sandbox than Python. Also, should you ever audit the source, it's 16,000 lines of C. Good luck auditing CPython.
- Open Source references. Yes, there are some projects that use Python. But they aren't OpenResty, Redis, HAProxy, nmap, wireshark, VLC, Asterisk, OpenWRT, PowerDNS, RPM, the NetBSD kernel...