If you think that using RubyMotion is going to make it so you don’t need to learn Objective-C… you are wrong.
In fact, you’ll probably need to know Objective-C and the Cocoa Touch API better than a newbie Objective-C programmer, because you really will need to understand the code. Newbie Objective-C coders can probably get by just cutting and pasting, but you’ll need to translate it.
That’s harder than you might think.
Agreed this doesn’t seems to help Ruby programmers to kick start iOS development.
However RubyMotion does provides some really juicy feature in the runtime debugger1, like changing variables in realtime for UIView’s frame, which is definitely something that we can’t easily do it with GDB or LLDB for now. This is demonstrated in the official Getting Started Video from 4:30 - 5:40
We’ll see how it goes.