[Radiant] Modifying configuration in an extension

[Wes Gamble]

 When I use a block like:

  extension_config do |config|
    config.after_initialize do
      ...custom stuff...
    end
  end
to manipulate the Rails configuration in an xxx_extension.rb file, is 
the config.after_initialize block important?  If so, why?

Thanks,
Wes