I think of it like 'Well'. Maybe the meaning is different but 'well' is a versatile word, and can be used to introduce information.
However, in English there is a difference between saying 'i'm fine' and 'well, I'm fine'. Well makes this phrase pregnant, there is more information to come.
But like you, I'd love to know more about this word. It's a similar case to me with 'Talaga' where the meaning can be understood, but to remove the word does not always appear to significantly change the meaning of the sentence.