Good thing you didn't bother, because it's absolutely not worth it. I chose LuaTeX initially precisely because it seemed more convenient to write commands in Lua than in plain LaTeX, but it turned into a total nightmare. Issues crop up as soon as you try to do something with text that embeds LaTeX macros, and the errors you get are even more byzantine than the ones you'd get by writing "normal" LaTeX code.
IMHO the very idea of embedding an external language into LaTeX is pointless, for the simple reason that LaTeX isn't markup, but code, and that it's pretty much impossible to parse it into a representation that makes sense and could be manipulated like, say, the HTML DOM. The only sane way to automate things is to write your documents in some language or markup that can be compiled to LaTeX, or to use a template engine.
The biggest thing LuaTeX gives you is variou hooks and access to various data structures used internally by the typesetting engine, so that you can work with them directly instead of having to do everything in a roundabout way through macro expansion. If all you need is text expansion then sure, just use TeX/LaTeX macros. (You mentioned "try to do something with text that embeds LaTeX macros"; I think working at the text level like that is a sign that your problem, or at least your solution, may not be a good fit for what LuaTeX gives.)
Here are a couple of my answers where LuaTeX was valuable; you can find hundreds more (IMO) by others:
- https://tex.stackexchange.com/a/379802 Avoid getting short words at line edges: Note that the macro-level solution runs into issues with \ref etc (just as you said about text that embed LaTeX macros), but the LuaTeX solution works perfectly in all cases
- https://tex.stackexchange.com/a/401315 Letter-spacing
- https://tex.stackexchange.com/a/403353 Typesetting on a poster with some image cut out
- https://tex.stackexchange.com/a/416772 Doing text replacements based on TeX macro state (maybe this could be done without LuaTeX?)
- https://tex.stackexchange.com/a/414013 Inserting random kerning
I do completely agree with your recommendation of generating TeX/LaTeX if possible (and keeping the macros/LaTeX to a minimum).
There's an analogous situation (or a continuation of this same situation, given the overlap in user base) for those who've invested decades in building a personal set of Emacs configuration files. Again, I've got thousands of lines of *.el files (many of them devoted to my idiosyncratic use of LaTeX) in my Emacs configuration. Of projects looking to replace the aged Elisp engine and create a modern implementation aren't going to get much consideration if it would mean replacing that (literally decades of) work in a different language. That's why I continue to be interested in Guile Emacs---less because of Guile (although I have no issues replacing Elisp with a modern Scheme), but because they've always made it clear that an ability to re-use Elisp configuration files was a primary design goal.