Mostly I just took issue with your usage of "scripting language" (which has more to do with a REPL and no discrete compilation step than anything else). The edit clarifies things a bit too; I confess to not following the original iOS app development details.

Thanks for taking the time to write an awesome response; you are definitely more savvy on the performance topic than me, and I'm disappointed to learn that the crunching power of modern mobile CPUs tends to be squandered.