There is no reason for a normal user to use MiamiDx. Miami is less overloaded with advanced features and therefore better for beginners. And for non-english people there are translations into different languages. Such don't exist for MiamiDx.
I guess I've gotten so used to MiamiDx that regular Miami now seems more complex to me because things I expect to be there aren't. As a native-English speaker, I wasn't aware MiamiDx wasn't localized - that's unfortunate. Thanks for brining it to my attention. Despite its shortcomings (speed, impossible to register) I find it very elegant and easy to configure.