What is the relation between "formatting problems" and Lua, and why "avoiding Mediawiki" would solve such problems you experiment? (and where do you experiment them?)
You wondered what was "mw" I just talk about it thinking it was obvious from the message I posted that already cited it.
Beside Mediawiki (which the the most important deployment of Lua in the world and used by the most important community of Lua programmers, after game developers and few techies working on small devices) are there really other major uses of Lua elsewhere? What caused Lua to become welknown worldwide instead of being confined to a Brasilian university where it started?
It's Mediwiki that popularized the Lua language for many by offering a major exposition to it. It has its local limitations (because of the Scribunto sandboxing, you can't use it to bind it with other languages or C modules, so yes it does not expose the LuaC API, only the Lua language itself and its standard library, with very few limitations for system calls and I/O). This is pure Lua. There's no I/O but support for a console, and returning text that can be displayed in a page, plus support for performing database queries, including updates, to Wikidata. It cannot be used to send mails or pilot some hardware device, the interaction is with a wiki website (not random external sites) in a controled environement that respect privacy rules of its community and operated under all other community rules.
It has also a support group, all is opensourced, documented, with bug trackers, project lifecycle management, talks, GitHub subprojects... Mediawiki is also not used just by Wikimedia and has a lot of plugins for specific sites that want them, and it supports many (>300) languages with active users groups in almost all countries of the world.
Wikimedia sites are also not restricted to use the MediaWiki syntax for wiki pages, even if Mediawiki is proeminent in its open content sites. It uses other independant tools as well with their own presentation/formatting. Mediawiki is just one of the tools that was needed for supporting the open content projects that can be used by lot of people. Various other tools and languages are also integrated: HTML, CSS, _javascript_, SQL, RDF, SPARQL, rest APIs, JSON, PDF, TeX, SVG,...Many formats are supported. Lua is just another one in addition to PHP, C, various SQL engines, data models, process models, for developing other extensions.
You may want to ignore it, but you cannot ignore it exists given its presence on the web in many sites and medias.
