I wanted to have just faster dynamic lang. Common lisp is there, but the performant implementations are heavy. CFFI is well developed, and systems like Lispworks allow you to create a dll with "C" entry point (but it's commercial and costs some money)
javascript's v8 was my next choice, but then found about luajit and using it since. The jit and the ffi are very good selling points. Also the small size of the project, and very fast recompile time (unlike say pypy)
I've used lua back in 2001, 2002 as a testing facility for a library I did at work.
I played with it a little ... but the 1-base of arrays is too painful right now.
I used to do Basic, Pascal, C, Assembly, Python, Fortran and a few more esoteric language in the same week (almost every week, for a couple of years. Old times ...), and back then, I had no trouble jumping between 0 base and 1 base. But it's been almost 20 years now that I've done 0 base exclusively. And I didn't have enough incentive to get comfortable with the 1-base again.
Very happy to finally see an official release!