Questions on UE4 Tutorial 4.8 (Inventory interface with UMG)

At Episode 5 ( ) of the series in the 18:45 time section Could someone explain to me Why do we have to bind all the buttons with the refresh script?

It’s a method of communication, the objects you work with need to know about one another. Using a dispatcher is an elegant solution in this case, allowing the buttons to send data back to the HUD.

Thank you for the clarification, it definitely helped