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

I agree.  To ask about “expensive” cables is a huge red flag.  If you want to discuss what your system is currently and the cables you have now we could discuss how certain choices may be an upgrade for you whether they are expensive or not.

Much better sound great definition better detail.Look at Purist a great cable from a co that will be here in the future.Enjoy!!

THose are advertised benefits.   Maybe yes, maybe no....  Same true at any price.

I smell a rat.

A big stinky rat