Makes no sense. Obj-C is compileable, and arguably faster to develop with auto-completion, code checking. There's no cross platform benefits, and it's not free.
RubyMotion is compilable as well, and auto-completion only helps when you're writing code, not when you're going back and re-reading it. Also, it was announced at the end of the RubyMotion conference that additional platforms are on the road map.
...and, as my grandfather always told me, you get what you pay for.
...and, as my grandfather always told me, you get what you pay for.