I think it kind of needed that over-the-top note, though. Without the sheer o_0-ness of a piano eating someone, it would be just a bland ghost story that never quite achieved the lyrical nostalgia it was aiming for and ended with a standard drag-you-to-hell ending. Making it more about the egregious, out-of-place piano helped make this more than some kind of occult PSA. Don't Do Black Magic, Kids!
I felt like the backstory about the ghost ship was shoehorned in there, but there was just no graceful way to include it, starting where the story did and with the particular voice and tone it chose. I don't know that the backstory really even needed to be there; a little speculation about the roughness of the wood or a particular carving on it might have served just as well, especially with the additional note of the image of the burning man on the boat in the occult tome she found.
Still, the story did a good job inserting subtly unsettling angles early on; the piano was creepy from the get-go, well before it should have been, so clearly the language was doing something right.