Idk, maybe because that particular "instrument" is not an instrument but just a visualized part of the ritual, like a key part?
Maaaaaybe.

And maaaaaaaaybe that is exactly what i find to be a missed opourtunity and would like to change?

I mean come on, that flute is basicaly the only object in WHOLE GAME that have apropriate size.

Basicaly everything else we can hold is ridiculously huge. :-/