Use cases for $evm.new_object

I see from the code that if I create a /var/www/miq/customer directory (I’m assuing that’s what File.join(Rails.root, “…”, “customer”) equates to), I can drop my own class definitions in there and call them with $evm.new_object. Can anyone provide a typical use-case for this? Would I be able to extend the rails classes that I typically can’t see from the automation engine?