Lua makes accessing REST APIs from the iPhone dead simple

Not that this means it's a good idea to include an interpreter under the assumption that Apple won't notice -- if they do notice & care, you'll find you will no longer be able to update your app.

Apple has also demonstrated a history of caring about certain violations at the most inopportune times -- lots of camera applications broke when 3.0 was released, and Apple wouldn't let the authors release updates, since the only way to implement the required functionality was through undocumented API.

In the case of Wax, Lua is embedded in the application itself and doesn't provide a VM which can host other applications.