On one hand, you do have JavaScript ubiquity, on the other hand, you have the JavaScript "WTF" equality and typing conversion matrix, "WTF" scoping, and dozens of other foot guns that Lua doesn't have. Some people would rather everyone learned Lua subtle differences and wrote less buggy code. I've had to use for the web for 20 years, and if I have any choice, I would avoid it.
Anyway, every language has some fans, and I don't mean to dismiss them, but ubiquity is not the top priority, all the time.
Anyway, every language has some fans, and I don't mean to dismiss them, but ubiquity is not the top priority, all the time.