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

want to upgrade,but not sure if its worth it.
   I would say cabling is system dependent more than anything. With 80% of the systems it doesn't matter because the system cannot resolve the difference. 
    My Living Room system which uses an above average receiver and OPPO player has old Monster and Audio Quest cables...I hear no difference in cable change outs. However my listening Room system which uses Technical Brain and heavily modified Silverline Grandeur mk II speakers is easy to hear. Schonberg makes a great bang for the bucks line of silver ribbon cables.
Price brings mostly the outward appearance differences.

There are three distinctly different sounding speaker cables.

  1. Regular stranded copper.
  2. Solid wire.
  3. True Litz (type 2).

Each one will sound different than the others.
Each one can be constructed to give the appearance to sell for big $’s. And, in turn. Each one can be made to sell for much less.
People with more money than they know what to do with will think big $’s cables must sound better. Someone out there is always willing to oblige them. They will definitely look better. Sound? Your choice. 1, 2, or, 3.
Is a $200 bottle of wine better than a $20 bottle of wine. Is it 10X better? Cable/wires can make your system sound different. Is that the same as better?
Maybe. It depends on what you are trying to find.
Here's some info to  sink your teeth into. Plenty of useful info from someone who does know what they are talking about.

You may already know the author is a known designer. At least you will have more perspective on your decision. 

Playing with audio, and navigating thru forums IS MADNESS!

Your linked article by Harry Marynard is very informative.

Harry describes the relationship between wire resistance, speakers’ varying impedance and the amplifier’s damping factor.  These issues were addressed in the posts by b4icu referenced by khaki above.

Athough b4icu excluded ribbon speakers from his reporting, I took his advice and connected four feet 0 AWG battery cable from a Pass Labs 250.5 (damping factor of only 150) and modified Magnapan MG IIIa’s.  Maggie’s have a difficult load ranging from 6 to 2 ohms.  The experiment was upgrading from 16 to 10 gauge wires tested previously.  The results were stunning.

The installed signal and neutral battery cable wires were separated by four inches to reduce the possibility of induction induced noise, see WiilyWonka’s post above.

Total cost, $65.

Given the modest cost and ease of installation, OP might start here and move on to IC’s.