Keep them short and at a standard length. Silver oxidizes differently and is usually cost prohibitive.
Some cables use silver plating effectively.
It looks good but is frequently applied over low quality base metals. Many high end interconnect cables without proper shielding or shield termination are hindering system performance. Not so critical for most speaker cables unless you are running them directly on AC power lines. It is better to attach a gold plated end which will resist corrosion or cover the end with silver solder. It helps reduce the effects of backflow EMF which can smear HF details.