It's not very significant (by most definitions of the word), a typical physics | engineering quote is:

    The electrical conductivity of copper is slightly higher at 5.96 x10^7 S/m than gold which is 4.11×10^7 S/m. More importantly is the lifespan of the two metals. Copper has a high oxidation level. So, if installed in an unstable environment (such as outside), it will fail sooner than gold.

They're close (which is how I misordered the two) with the corrosion Vs non corrosion of copper V. gold being a factor in switch contact lifespans - typically high copper alloys with lower oxidation rates are used.

It is significant enough that you would need a thicker wire for many applications. Gold's corrosive properties are often useful and it conducts well enough, though even then gold is used as much because of "gold" when something else cheaper would work good enough.

Gold-plated connectors don’t oxidize- which is a benefit over copper alone.

Gold does not corrode, and can be formed into thinner parts.

And as an added bonus, copper jewelry turns your skin green!

/s