E-3 plugs worth the money?

Sorry, not to stir the pot but I'm majoring in science and I'll have to add this:
In truth Copper is the second most conductive metal in the world.
Silver is the best. HOWEVER Silver is more expensive, fragile, prone to tarnishing and therefore not very feasible to use.
Ask me how I know... I missed one question on my frickin' exam and I thought the answer was Copper, I challenged the question with my professor... I lost the argument and about $8.00 as I had to buy him lunch.