In the case of copper, for instance, recovering that metal from e-scrap produces 65% less CO2 than if the same amount of copper is produced from the smelting of copper concentrate produced by a mine. Furthermore, the process of mining copper, and producing a copper concentrate, emits about 3 tonnes of CO2 into the atmosphere for every tonne of copper produced!
For some other metals (including aluminium, gold, lead and the so-called rare earth elements) these effects are even bigger.
Since we want to reduce the amount of energy we use, and we want to reduce the amount of CO2 produced, it would be a very bad idea allow these various metals to end up in a landfill.
Products that no longer function, and which contain these metals, should therefore be recycled as efficiently as possible.