Because if you can just use a special syntax to acess the extended attributes, that makes them immediately accessible to the shell, scripts of various types, and programs that don't know how to access the attributes natively.
For example, clearcase is a (commercial) version control system. It implements something like this by allowing you to append @@ to any file within it and from there see all the versions and branches that are available. This is very powerful, as you can do things like using tab completion in BASH, direct scripting, etc. It's very nice.
Copyright © 2017, Eklektix, Inc.
Comments and public postings are copyrighted by their creators.
Linux is a registered trademark of Linus Torvalds