What's the deal with language copies - Do they do anything other than create an exact copy of the parent language branch?
If instead of using the language copy option, if I just go to crxde Lite and create a copy of the language branch and rename the language node to the new ISO code, do I stand to lose anything vis-a-vis doing the same thing using the Language Copy option?
there are two option either you create language copies for translations project then its useful to send out a package to translation agencies. This will create translation project per language for selected pages. It will give you option to export the package for human translation to send to agencies, once you receive it back, after importing it will put the translations back to created language copies removing the effort to cut and paste translations manually. if its an update to existing one i.e., the a language copy already exists, it will create another copy without overwriting the current one.
If you are just after copy as it is from source ie English, you can just select the option create structure only and it will only create copy of source file with no translation project.
Using CRXDE to do this i would not suggest unless experimenting for development.