I wrote this a year ago, it is part of a much larger text. It's probably not very interesting for most people!
"An army that regularly parades in public displays itself as a highly professional army. Even though the parade itself does not perform any useful function on a battlefield, it has an affect even in times of peace and in build-ups to wars. A rag-tag army is likely to be unable to put on parades, hence it holds that larger and better armies can display their discipline by means of public performances. It therefore acts as a psychological tool and a deterrent - it says that the army is ready, strong and trained."