1. Lua embeds well on a small system and gives us a higher level language than C. lua or luajit is ok
2. Lua isn't being used for performant code. If we have performance issues use C.
3. LuaJit is looking for a maintainer and is stagnant. This isn't desirable.
Not sure if this is "best practice" but it summarized how we worked through it.
Lua 5.4 has some appealing benefits for us, we'll give it a few patch releases, but I look forward to moving to it.
Re Performance: We're actually running from 50Hz code in Lua on an old embedded CPU. We haven't re-written that in C yet since it runs just fine. We're been constantly surprised at how well it runs and works for us.