Piano Forum

Hello.

This is my take on it, I'm going mostly from an audible perspective, but there may even be technical perspectives as well (a composer wanting a note to sound, but knowing it could be difficult to reach the next note, may use a rest and sustain pedal as a way around this)

A rest is an indication to the performer that nothing is to be Played in that specific beat(s) NOT nothing is to be heard

Assuming you've done your homework, Chopin is the perfect example and so noted in your post. He took sound to the next level with regards to the piano, even as much as to be able to tell which finger you used to press a particular note (reference from a piano lesson quoted by one of his students)

Now the fact is, and particularly more notable in pianos of the time of Chopin is that a note held down is an audibly different sound to a note pressed and sustained (I think the actual sound died off particularly quickly on sustained notes on this generation of pianos).

I believe there was even an article I read that quoted Chopin on another pianists playing, criticizing him in the fact that he played mostly from the pedal.

And so my conclusion is that, that's the sound he wanted.

EDIT

Taking a look at the particular bar, the Ab Octave is followed immediately by an Ab 9th above.  Potentially this is a technical point, as nobody can instantly travel to those notes, the rest gives you time to break.