I use cabe risers for one reason only. They dress up the wires running across the floor. I have wood floors so the only reason mentioned would not even apply in my case. I use antique glass power line insulators that I got on Ebay for about $2 EACH. So, in my case, for only $16 I dressed my cabless to my SO's satisfaction. I bi-wire (let's not get started on the effectiveness of that...) so it actually looks like mini power lines running just above the floor!
So, for me, the only reason is aesthetics.
So, for me, the only reason is aesthetics.