There are certain scenarios where content is getting lost when more than one person works on an article.
So here's one scenario.
Writer A creates an article. Adds a few lines to it... and then stops. After 15 minutes, the article is unlocked.
Writer B sees that they are able to edit the article and adds a few more lines. 15 minutes passes and the article is unlocked.
Writer A - who hasn't saved the page since starts to edit the page ... makes changes - now saves the page.
Writer B's edits are lost.