could somebody help me out on the benefits of expensive phono and speaker cables?

Just remember, cables ARE tone controls. Certain cables don't, "Get out of the way of the music", like so many people claim.  They all add their own signature.  Some add more air, depth, width, etc., than others. You have to see what works best for your tastes. 

Don't get sucked into the hype of uber expensive cabling. Cables are the biggest racket in audio.