What are the advantages of using Builder over regular xml files?

[CrerCasepooth]

I have a Rails application which is using the Builder gem for writing easy to use XML files.I am very much satisfied with the Builder gem but, as per my product architect's view, we should always use simple .xml files instead of using third party tools.So, I need to give a solid justification to him explaining to him about the advantages of using Builder over regular XML files in our Rails application.Can anyone give or guide me to a valid justification on the usage of Builder over regualr RXML/XML files in a Rails application?