matchbox and that old admin folder question

[eluser]hyperfire[/eluser]
Seriously? I need to use that then use a route to get:
example.com/admin/blog
and
example.com/blog
example.com/blog/post/3

and so, what about that configuration on matchbox.php
$config['directories'] = ('modules');

can i add ('modules', 'admin')

and have

admin/blog
blog

Sorry...im trying to get it and found this topic discussed many times without a clear 'theme' for this.
If i need to route, why use matchbox? Just for organization sake?
Thanks