Currently, Facebook Stories and Messenger Day can only be used by individuals and not by pages/companies. This is quite a difference from Snapchat or Instagram which allow different kinds of users.
This is why Facebook Stories and Messenger Days can be used now for companies that are still small and can use a personal page to interact with their customers or fans in a more personalized way through these tools. The features provide a great way to share some small insights, daily activities within the company, small updates and events that are happening such as conferences as well as other several advantages. These could be through having the followers associate the company/brand/product with the people presenting it and viewing how the company is growing as well
There are of course some advantages to using a personal profile over a page on Facebook which you can check out by the time that Facebook incorporates these features for pages!