I thought this was actually a great moment, I peered over the edge of the platform into the lake and thought surely, I'm not supposed JUMP in there am I? Then the old man in the chair wordlessly points to that exact conclusion. I loved it.
I get your point, there are some parts that are straight up missing in the final game, I think what they shipped is Bloodborne v0.6 because there are a lot of half baked ideas here. Like when you beat Vicar Amelia, apparently you are given the password to the forgotten woods, but damned if they give you any indication as such other than a vague item description.