Lua also has operational advantages compared to javascript. You can build it from source in at most a few seconds and run it anywhere that has a c compiler. The startup time is negligible even compared to a compiled c program so you can run entire scripts that do very useful things faster than most js engines can print hello world. There is also the benefit that in spite of what this article discusses, it is possible for most problems to write a lua solution that works for all lua >= 5.1. This is wonderful because it means if I stick to the standard library, the bitrot is essentially zero.
Calling into c is very straightforward in Lua, especially with luajit, which makes it superior to js as a scripting language (the node ffi api is quite painful in my experience and ffi runs against the js execution model).
Lua also essentially got lexical scoping of local variables correct from the beginning while js blessed us with the nightmare of var.
Of course Lua is far from perfect, but while there are some similarities, the differences are quite significant and meaningful.