Benefits of Bi Wiring is it worth the extra cost?

I am in the process of looking to upgrade my speaker cable and during the past two weeks have borrowed a demonstration pair of Black Rhodium Tango Cable, these are the non bi-wired type.I have been impressed with the performance of these cables they have really opened up the sound coming from my speakers.

Having been impressed with the benefits I am thinking is it worth the extra additional cost and get a pair of cables that are suitable to bi wire at the speaker terminals.

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