@jmlepstein But a more obvious reason would be e.g. a song transposed down more than 5 steps; many songs might sound more 'heavy' or even muddier. And when you transpose up the song might lose some depth and warmth. I wish I had better words to describe it lol.
@jmlepstein Yup
At least one reason that I can think of rn is that on an acoustic piano, the tone of each key is subtly different, thus giving a slightly different tonal character to the transposed version.
@ilyasut Perhaps one day someone will mathematically (dis)prove that the working of either kind of neural unit, albeit different, leads to a system with the same behaviour and capabilities. Which in turn could lead to interesting possibilities for alien intelligence too.