The DialogueChoice struct is created and used while setting up a DialogueTree. The Branch() function will pass the DialogueChoice to its corresponding nodes at runtime. The text for this struct is used as this individual choice's text.
This bool checks a condition to decide at runtime if a choice should be sent to the DialogueManagerSubsystem to broadcast for presentation through the OnDialogueChoices() event. If false, the array of choices sent will include an empty string in whichever array element this DialogueChoice is.
This is the key used to find the dialogue text from the associated string table when making the struct in the Blueprint editor.