Are you telling me silver and copper sound the same? They have different electrical properties, different capacitance and inductance, so the question is, do you think they both sound the same?
No, I am just suggesting that your assertion that speed is faster in silver is wrong.
Capacitance and inductance are primarily characteristics of the cable construction.
If we narrow the debate to speaker cables (that is high current, low frequency domain), in my opinion there should be an audible difference between cables if they differ in say resistance (as copper and silver cables of the same diameter would).
The primary reason is that loudspeaker impedances vary greatly with frequency, especially in cross-over regions. The impedance of the speaker and the resistance of the wire are in series. Changing the wire resistance means relatively more or less power is delivered to the speaker over different parts of the audible spectrum, changing the tonal balance for those with golden ears.
Also pure copper is far from an "excellent connector". For the same reason you stated, its softness and malleability, the opposite of what a good connector represent.
The malleability of pure copper means that those ’uneven’ bumps present on any surface get squished into the holes, providing more contact area especially in spade configuration. The ideal connector has no discontinuities and no contamination - I am thinking of friction or pressure welds.
Of course it is no good if it breaks!