When I see Lua, the only thing I ever read is "great for embedding", "fast", "lightweight" and more often than anything else: "World of Warcraft" or in short "WoW".
Why is it limited to embedding the whole thing into another application? Why not write general-purpose scripts like you do with Python or Perl?
Lua seems to be doing great in aspects like speed and memory-usage (The fastest scripting language afaik) so why is it that I never see Lua being used as a "Desktop scripting-language" to automate tasks? For example:

Renaming a bunch of files
Download some files from the web
Webscraping

Is it the lack of the standard library?
Definitely a lack of standard libraries.  It's also lesser known than Python, Perl or Ruby.
Lua as a general-purpose scripting language?