As Umbra say ...
We dont know the full scale yet.
Sure Narator is not (as it seems so far) "a character", Narator represents our mind, our inner voice ...
But if that inner voice, our mind, our memory and stuff are twisted by the power of "some entity" so we tend to like her more, it kinda makes sense to me that voice will talk to us in seductive way.
I mean, when you say narator i imediatly remember that part when you pick up the tadpole from Eodwin.
When she was talking about how the tadpole recognize you as one of its own ... it seems logical to me that her voice is smooth as silk and captivating, almost intrusive. The tadpole is twisting your mind to like it, and your inner voice reacts on that in brilliant display of rule "show, dont tell".
But yes, there is allways option that someone in Larian just thought it would sound better this way and there is no deep thought behind it.
