SharePoint has many uses, besides just document storage. It can be used as a daily intranet site, one that can display many different types of data. If there is enough traffic being driven to your SharePoint site, you can add apps and web parts that allow you to display important announcements, such as the company holiday party. Since everything in SharePoint has a URL associated with it, you can create items and add direct links to those items in emails, events, or messages that you send to all personnel. In many cases, this is simpler than explaining where to go, since everyone just clicks a link to see the item.
Watch the video to see how an announcement is added in SharePoint: