Mining. In cryptocurrency networks, mining is a validation of transactions. For this effort, successful miners obtain new cryptocurrency as a reward. The reward decreases transaction fees by creating a complementary incentive to contribute to the processing power of the network.
It matters because the actual coffee flavor is extracted from grind better at higher temperatures. I'm not a scientist but I trust those that have done the research and they say that the optimal temperature for hot water in a coffee pot is between 195-200 degrees or just a little under boiling.
This material is a solid at room temperature but will melt into a liquid when heated by the coffee. This melting sucks out just enough heat to cool the coffee to 140 degrees and transfers small bits of that energy back into the liquid over a long period of time to maintain the 140 degree mark.